Environmental Science: Nano最新文献

Mine water discharges pose a significant environmental challenge due to elevated metal concentrations, which can be detrimental to aquatic ecosystems and water quality. In this study, four circumneutral-pH mine water samples were treated with different magnetic nanoparticle (MNP) concentrations (0.1 g L⁻¹, 1 g L⁻¹, and 5 g L⁻¹) to assess their efficacy for Zn removal. Sorption of Zn to all MNP systems tested, occurred within 48 hours. At 5 g L⁻¹, MNPs removed Zn from all mine waters tested, reducing concentrations to 0.09, 0.66, 0.0 and 0.0 mg L⁻¹ for the River Ystwyth, Cwmystwyth adit, River Nent and Haggs adit respectively. A clear positive correlation was recorded for Zn removal as a function of MNP dose, with MNP concentrations >1 g L⁻¹ required for Zn removal to below trace concentrations. Analysis of competing ions (e.g., Ca²⁺, Mg²⁺, Na⁺) showed that a decrease in concentration followed the order Zn > Na⁺> Ca²⁺ > Mg²⁺. These findings confirm that MNPs are effective for the removal of Zn from real mine water samples even when applied at low dosages, suggesting that they are a highly promising water treatment technology for such applications.

Oilseed rape (Brassica napus L.) cultivation increasingly faces challenges from arsenic (As) contamination, which disrupts plant metabolism through oxidative stress and antioxidant enzyme inhibition. This study investigated the potential of manganese nanoparticles (MnNPs) to alleviate As toxicity across five genetically distinct B. napus cultivars under hydroponic conditions. Plants were exposed to varying concentrations of As (0, 100, and 200 μM) and MnNPs (0, 50, and 100 μM) to evaluate treatment efficacy. Results demonstrated that As stress (200 μM) severely reduced leaf fresh weight (43.88–77.57%), root fresh weight (69.35–91.2%), and photosynthetic efficiency while significantly increasing reactive oxygen species (ROS) accumulation across all cultivars. Conversely, the application of 100 μM MnNPs substantially ameliorated these effects, increasing leaf fresh weight by 25.26–70.65%, improving photosynthetic rate by 61.94–77.27%, and restoring stomatal conductance by 43.48–58.83% compared to As-only treatment. Additionally, MnNPs significantly reduced oxidative stress markers in both leaf and root tissues while upregulating antioxidant enzyme activities beyond levels induced by As stress alone. Metabolic analysis complemented these physiological findings, revealing variety-specific profiles with ZD 622 exhibiting high hexenol acetates, while the combined MnNPs + As treatment induced the strongest metabolic response, suggesting synergistic stress defense effects. Notably, cultivars exhibited distinct genotype variations, with ZD 635 and ZY 758 demonstrating superior As tolerance following MnNP treatment, whereas ZD 622 showed the least tolerance. These findings collectively highlight MnNPs' effectiveness in enhancing B. napus productivity in As-contaminated environments by improving stress tolerance mechanisms, underscoring their potential as a valuable nano-agronomic intervention.

This research involved a comprehensive multisystemic evaluation of the biotoxicity of three tracers (carbon quantum dots synthesized from citric acid and ethylenediamine “N-CQD”, commercial cadmium-tellurium quantum dots “CdTe-QD”, and a conventional tracer based on fluorinated benzoic acid derivatives “SB-tracer”). Biotoxicity was assessed at three organizational levels: DNA, cellular, and multicellular eukaryotic system, using the comet assay and chromosomal aberration tests, cytotoxicity assays, and plant growth profiling, respectively. The results revealed significant DNA damage induced by CdTe-QD and SB-tracer, with olive tail moment (a measure of DNA degradation) values up to 15 times higher than those observed for N-CQD in the comet assay. Cytotoxicity revealed an half maximal inhibitory concentration (IC₅₀) > 1000 mg L⁻¹ for N-CQD, 7.35 mg L⁻¹ for CdTe-QD, and 600.06 mg L⁻¹ for SB-tracer, classifying the samples as non-cytotoxic, cytotoxic, and moderately cytotoxic, respectively. However, the chromosomal aberration results for SB-tracer revealed its lethality by inhibiting the lymphocyte proliferation required for the test. Melon and sunflower seed sprouts were employed as multicellular eukaryotic models for toxicity evaluation at higher organizational levels, and it was observed that SB-tracer has a deleterious effect on germination, while N-CQD increased sprout biomass by up to 19 times compared to water irrigation, a result attributed to their positive effect on photosynthetic mechanisms. Finally, the non-toxic and protective effects of N-CQD can be attributed to their high ORAC (oxygen radical absorbance capacity) value considered in this research, which is associated with the prevention of damage to key biomolecules such as DNA and the promotion of cell growth. These results highlight the feasibility and potential use of CQDs as a safe alternative for both the environment and health, with the potential to substitute substances conventionally employed by different industries as multipurpose tracers. To the best of our knowledge, this is the first study to comprehensively evaluate the biotoxicity of QDs at multiple biological organization levels.

With the increasing release of nanomaterials into soil ecosystems, the intensity of combined exposure to nanomaterials and metalloids/heavy metals are rising, highlighting the urgent need to understand their joint toxicological effects of nanomaterials and metalloids/heavy metals. In this study, the ecotoxicological impacts of the co-exposure of molybdenum disulfide nanomaterials (MoS₂ NMs) and the metalloid arsenic (As) in soil are explored. Specifically, a pot experiment was conducted to investigate the toxic effects of combined exposure to As (25, 50, and 100 mg kg⁻¹ soil) and MoS₂ NMs (30 mg kg⁻¹ soil) on earthworms. Key parameters including earthworm growth, bioconcentration, physiological and biochemical responses, and gut microbial metabolism were assessed. Soil and earthworm samples were collected on the days 7, 14, and 28 post-treatment. The results revealed that the co-exposure of MoS₂ NMs and As increased the As accumulation in earthworms by 16.3%, 26.7%, and 12.4%, and reduced their body weights by 39.5%, 34.9%, and 28.1%, respectively, compared to the single exposure of As. This co-exposure aggravated pathological damage, elevated oxidative stress, and significantly increased the integrated biomarker response index. Furthermore, it disrupted the balance of gut flora and metabolic pathways in earthworms and enhanced their toxicity. This study provides new insights for evaluating the ecological and health risks associated with the simultaneous presence of nanomaterials and metalloids/heavy metals in soil environments.