Chronic toxicity of ZnO nanoparticles, non-nano ZnO and ZnCl2 to Folsomia candida (Collembola) in relation to bioavailability in soil

The chronic toxicity of zinc oxide nanoparticles (ZnO-NP) to Folsomia candida was determined in natural soil. To unravel the contribution of particle size and free zinc to NP toxicity, non-nano ZnO and ZnCl₂ were also tested. Zinc concentrations in pore water increased with increasing soil concentrations, with Freundlich sorption constants K_f of 61.7, 106 and 96.4 l/kg (n = 1.50, 1.34 and 0.42) for ZnO-NP, non-nano ZnO and ZnCl₂ respectively. Survival of F. candida was not affected by ZnO-NP and non-nano ZnO at concentrations up to 6400 mg Zn/kg d.w. Reproduction was dose-dependently reduced with 28-d EC50s of 1964, 1591 and 298 mg Zn/kg d.w. for ZnO-NP, non-nano ZnO and ZnCl₂, respectively. The difference in EC50s based on measured pore water concentrations was small (7.94-16.8 mg Zn/l). We conclude that zinc ions released from NP determine the observed toxic effects rather than ZnO particle size.     

氧化锌纳米颗粒对SBR中活性污泥脱氮性能及硝化细菌丰度的影响

在SBR中添加氧化锌纳米颗粒（ZnO-NPs）,研究ZnO-NPs对活性污泥脱氮性能及硝化细菌丰度的影响。结果表明,低浓度（1 mg·L-1）ZnO-NPs对活性污泥脱氮性能无影响,高浓度（10、50 mg·L-1）ZnO-NPs可抑制活性污泥硝化性能,且对硝化菌活性抑制作用小于亚硝化菌。ZnO-NPs浓度梯度增加至50 mg·L-1较直接投加50 mg·L-1 ZnO-NPs对污泥活性抑制作用小。高浓度ZnO-NPs改变活性污泥微生物胞外聚合物（EPS）产量和性质。SBR运行结束时,高浓度ZnO-NPs的添加导致亚硝化菌相对丰度大幅度减小,而对硝化菌相对丰度影响较小。     

Distribution and bioavailability of ceria nanoparticles in an aquatic ecosystem model

Along with the increasing utilization of engineered nanoparticles, there is a growing concern for the potential environmental and health effects of exposure to these newly designed materials. Understanding the behavior of nanoparticles in the environment is a basic need. The present study aims to investigate the distribution and fate of ceria nanoparticles in an aquatic system model which consists of sediments, water, hornworts, fish and snails, using a radiotracer technique. Concentrations of ceria in the samples at regular time intervals were measured. Ceria nanoparticles were readily removed from the water column and partitioned between different organisms. Both snail and fish have fast absorption and clearance abilities. Hornwort has the highest bioaccumulation factors. At the end of the experiment, sediments accumulated most of the nanoparticles with a recovery of 75.7 ± 27.3% of total ceria nanoparticles, suggesting that sediments are major sinks of ceria nanoparticles.     

DNA磁性纳米颗粒对水中菲的吸附性能

多环芳烃(polycyclic aromatic hydrocarbons, PAHs)作为一种致癌污染物,在水体中分布广泛且容易在生物体内富集,对人体健康有着严重的威胁。本研究将DNA与磁性纳米颗粒结合作为吸附剂,利用DNA与多环芳烃化合物的嵌入结合原理去除水体中的菲,分别考察了时间、菲的初始质量浓度、温度等因素对DNA结合菲的影响,以及对DNA磁性纳米颗粒去除菲的影响。结果表明：在35 ℃、pH=7.4、时间为50 min的条件下,在DNA的质量浓度为0.1 mg∙mL⁻¹、菲的初始质量浓度分别为150、200、250 μg∙L⁻¹时,结合率分别为95.47%、93.46%、91.14%。在相同条件下,DNA磁性纳米颗粒用量为1 mg、菲的初始质量浓度分别为100、150、200、250 μg∙L⁻¹时,去除率分别为96.47%、95.61%、93.46%、88.03%,吸附量分别为96、143、187、220 μg∙g⁻¹。DNA磁性纳米颗粒对菲的吸附过程符合准二级动力学模型和Langmuir模型,热力学参数表明吸附过程是自发和吸热的。DNA磁性纳米颗粒作为吸附剂可用于去除污水中的菲,以上研究结果可为基于PAHs-DNA嵌入结合作用处理污水中的菲提供参考。     

In vivo genotoxicity assessment of titanium,zirconium and aluminium nanoparticles,and their microparticulated forms,in Drosophila

As in vivo system, we propose Drosophila melanogaster as a useful model for study the genotoxic risks associated with nanoparticle exposure. In this study we have carried out a genotoxic evaluation of titanium dioxide (TiO₂), zirconium oxide (ZrO₂) and aluminium oxide (Al₂O₃) nanoparticles and their microparticulated forms in D. melanogaster by using the wing somatic mutation and recombination assay. This assay is based on the principle that loss of heterozygosis and the corresponding expression of the suitable recessive markers, multiple wing hairs and flare-3, can lead to the formation of mutant clones in treated larvae, which are expressed as mutant spots on the wings of adult flies. Third instar larvae were feed with TiO₂, ZrO₂ and Al₂O₃ nanoparticles, and their microparticulated forms, at concentrations ranging from 0.1 to 10 mM. Although a certain level of aggregation/agglomeration was observed in solution, it must be noted than the constant digging activity of larvae ensures that treated medium pass constantly through the digestive tract ensuring exposure. The results showed that no significant increases in the frequency of all spots (e.g. small single, large single, twin, total mwh and total spots) were observed, indicating that these nanoparticles were not able to induce genotoxic activity in the wing spot assay of D. melanogaster. Negative data were also obtained with the microparticulated forms. This indicates that the nanoparticulated form of the selected nanomaterials does not modify the potential genotoxicity of their microparticulated versions. These in vivo results contribute to increase the genotoxicity database on the TiO₂, ZrO₂ and Al₂O₃ nanoparticles.     

Synthesis of isotopically modified ZnO nanoparticles and their potential as nanotoxicity tracers

Understanding the behavior of engineered nanoparticles in the environment and within organisms is perhaps the biggest obstacle to the safe development of nanotechnologies. Reliable tracing is a particular issue for nanoparticles such as ZnO, because Zn is an essential element and a common pollutant thus present at elevated background concentrations. We synthesized isotopically enriched (89.6%) with a rare isotope of Zn (⁶⁷Zn) ZnO nanoparticles and measured the uptake of ⁶⁷Zn by L. stagnalis exposed to diatoms amended with the particles. Stable isotope technique is sufficiently sensitive to determine the uptake of Zn at an exposure equivalent to lower concentration range (<15 μg g⁻¹). Without a tracer, detection of newly accumulated Zn is significant at Zn exposure concentration only above 5000 μg g⁻¹ which represents some of the most contaminated Zn conditions. Only by using a tracer we can study Zn uptake at a range of environmentally realistic exposure conditions.     

CuONPs短期暴露对SBR水处理效果的影响

研究了不同浓度氧化铜纳米颗粒(CuO NPs)对序批式活性污泥工艺(SBR)中化学需氧量、氨氮、总磷、硝态氮和亚硝态氮去除率的影响.实验结果表明,当环境中浓度为1 mg/L和10 mg/L的CuO NPs短期暴露时(1 d),其对活性污泥生存能力和周期内有机物去除、脱氮除磷都没有造成急性影响.经过20 d的短期运行,对SBR系统出水COD、氨氮、总磷、硝态氮和亚硝态氮也没有造成明显的影响.活性污泥呼吸抑制实验结果显示,CuO NPs对活性污泥的呼吸抑制作用与浓度呈正相关性,浓度越高呼吸抑制现象越明显,低浓度CuO NPs对活性污泥活性并没有明显的抑制作用.     

Responses of a soil bacterium, Pseudomonas chlororaphis O6 to commercial metal oxide nanoparticles compared with responses to metal ions

The toxicity of commercially-available CuO and ZnO nanoparticles (NPs) to pathogenic bacteria was compared for a beneficial rhizosphere isolate, Pseudomonas chlororaphis O6. The NPs aggregated, released ions to different extents under the conditions used for bacterial exposure, and associated with bacterial cell surface. Bacterial surface charge was neutralized by NPs, dependent on pH. The CuO NPs were more toxic than the ZnO NPs. The negative surface charge on colloids of extracellular polymeric substances (EPS) was reduced by Cu ions but not by CuO NPs; the EPS protected cells from CuO NPs-toxicity. CuO NPs-toxicity was eliminated by a Cu ion chelator, suggesting that ion release was involved. Neither NPs released alkaline phosphatase from the cells’ periplasm, indicating minimal outer membrane damage. Accumulation of intracellular reactive oxygen species was correlated with CuO NPs lethality. Environmental deposition of NPs could create niches for ion release, with impacts on susceptible soil microbes.     

生物法/人工湿地工艺处理采油废水及其生态毒性削减研究

采用2种生物法/人工湿地工艺(水解酸化/好氧/人工湿地工艺和水解酸化/人工湿地(进水区强化曝气)工艺)处理胜利油田某联合处理站经隔油、混凝处理的采油废水,并运用发光细菌技术研究采油废水在处理过程中的生态毒性削减规律.研究结果表明,在水解酸化段水力停留时间(HRT)为20 h,好氧段HRT为10 h,人工湿地HRT为2 d的工况下,水解酸化/好氧/人工湿地工艺与水解酸化/人工湿地(进水区强化曝气)工艺的出水水质均能满足COD≤80 mg/L、NH_4~+-N≤15 mg/L的处理要求.发光细菌法试验结果表明,经隔油、混凝处理后的采油废水属高毒性废水,再经水解酸化/人工湿地(进水区强化曝气)工艺处理后生态毒性大幅削减,出水生态毒性降至低毒.     

SBR中纳米氧化锌和四环素复合投加系统对污泥胞外聚合物的影响

为研究氧化锌纳米颗粒(ZnO-NPs)和四环素(TC)对SBR系统内活性污泥胞外聚合物(EPS)特性的响应变化,在模拟室外光照条件下,考察了递增浓度ZnO-NPs和TC单独或复合投加方式下对EPS中蛋白质和多糖的影响。结果表明：ZnO-NPs、TC和复合投加系统中EPS的蛋白质含量均明显高于多糖,在各系统中,低浓度的投加量对蛋白质和多糖的含量改变无明显影响;随着浓度的递增和反应周期的延长,相比于空白组,ZnO-NPs系统中的蛋白质和多糖含量分别下降了33.58%和64.75%;TC和复合投加系统中蛋白质含量分别升高了57.86%、68.58%,多糖含量分别下降了43.60%和40.38%,且2个系统蛋白质和多糖含量变化趋势相似,因此,判断复合投加系统可能受TC影响较大。FT-IR分析显示,ZnO-NPs、TC和复合投加系统主要对EPS中蛋白质和多糖中的—OH、—NH₂、C=O、C—OH及C—O产生影响。3D-EEM分析表明,EPS中蛋白质基团受到主要影响。该研究可为纳米颗粒和抗生素共存情况下对污泥EPS的影响提供依据。     

磁性Fe3O4纳米颗粒的制备及在水处理中的应用

众所周知,纳米颗粒在去除水中污染物的过程中易团聚,还会造成水体的二次污染。磁性Fe3O4纳米颗粒因其能迅速从水中分离的特性而被广泛关注。改性之后的磁性Fe3O4纳米颗粒在水中污染物的去除方面有很好的应用。对磁性Fe3O4纳米颗粒及其载体或复合物的制备方法进行了概述,重点对水中污染物的去除从3个方面进行了阐述:磁性Fe3O4纳米材料对水中重金属的吸附、有机物的吸附及水中细菌和医疗废物的处理。     

Fate and behaviour of phenanthrene in the natural and artificial soils

For the assessment of contaminated soils ecotoxicological tests are used to estimate the bioavailability of contaminants in soil samples. Terrestrial tests reveal the habitat function of soils, and parameters applied in tests involving microorganisms include respiration activity and potential ammonium oxidation. For such tests, the threshold values needed to assess the results have already been established in guidelines ISO 17155 and ISO 15685. In this paper, we discuss about the respiration activity and potential ammonium oxidation results obtained from a wide variety of soils with different physico-chemical properties and levels of contamination. These results show that microbial respiration and potential ammonium oxidation have different sensitivities to various classes of contaminants. We demonstrated that both organic and inorganic contaminants influence potential ammonium oxidation, whereas microbial respiration is predominantly affected by biodegradable organic contaminants. These differences might be useful for more detailed assessments of soil contamination, leading to different recommended actions depending on which parameter is affected.     

CTAB调控绿色合成纳米氧化铁及去除亚硝酸盐

采用阳离子表面活性剂十六烷基三甲基溴化铵（CTAB）改性绿色合成纳米氧化铁（IONP）,提高其稳定性和分散性,并应用于去除水中亚硝酸盐。实验结果表明,亚硝酸盐初始浓度为20 mg·L-1,反应温度 30 ℃时,0.4 mmol·L-1 CTAB改性的绿色合成纳米氧化铁（CTAB-IONP）去除亚硝酸盐的效率最高,为 97.32%,比IONP增加了 23%。通过扫描电镜（SEM）和傅里叶变换红外光谱（FTIR）表征可知,经CTAB改性提高了IONP的稳定性和分散性,同时使其带正电,从而提高了反应活性。IONP对亚硝酸盐的去除反应遵循伪一级动力学,而CTAB-IONP则更符合伪二级动力学。     

Antimicrobial potential of commercial silver nanoparticles and the characterization of their physical properties toward probiotic bacteria isolated from fermented milk products

The application of nanotechnology in the agriculture and food sector is relatively recent compared to its usage in drug delivery or pharmaceuticals. Therefore, this paper presents a study of the effect of silver nanoparticles on probiotic bacteria based on the example of Lactobacillus acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12 and Streptococcus thermophilus ST-Y31 isolated from fermented milk products. Probiotic bacteria are one of the most crucial groups of bacteria for the food industry, because of their claimed health-promoting properties. Studies have shown that the type and concentration of silver nanoparticle solutions have a significant impact on the tested probiotic bacteria which are profitable for the digestive system. In the presence of all tested silver nanoparticles, St. thermophilus ST-Y31 growth was inhibited significantly by the dilution method as opposed to the disk-diffusion method. Both the disk-diffusion and the dilution methods showed no significant differences between L. acidophilus LA-5 and B. animalis subsp. lactis BB-12. The concentrations 2 μg mL^?1 and 0.25 μg mL^?1 had the highest antibacterial activity and statistically significant impacts on the tested probiotic strains. To our knowledge, this is the first report on potential antimicrobial effect of nanosilver against the health-promoting probiotic bacteria L. acidophilus LA-5, B. animalis subsp. lactis BB-12 and St. thermophilus ST-Y31 isolated from fermented milk products.     

Adsorption and breakdown of penicillin antibiotic in the presence of titanium oxide nanoparticles in water

The fate and transport of antibiotics in natural water systems is controlled in part by interactions with nanometer (10⁻⁹ m) metal oxide particles. Experiments were performed by mixing solutions of ampicillin (AMP), a common, penicillin-class human and veterinary antibiotic, with 25 nm-TiO₂ (anatase) nanoparticles at different pH conditions. Both sorption and degradation of AMP were observed in the AMP-nanoparticle solutions. For AMP concentrations from ∼3 μM to 2.9 mM the overall AMP removal from solution can be described by linear isotherms with removal coefficients (K_r) of 3028 (±267) L kg⁻¹ at pH 2, 11,533 (±823) L kg⁻¹ at pH 4, 12,712 (±672) L kg⁻¹ at pH 6, and 1941 (±342) L kg⁻¹ at pH 8. Mass spectral analysis of AMP solutions after removal of the solid nanoparticles yielded ions that indicate the presence of peniclloic acid, penilloic acid and related de-ammoniated by-products as possible compounds resulting from the degradation of AMP at the TiO₂ surface.     

Zero-valent iron nanoparticles in treatment of acid mine water from in situ uranium leaching

Acid mine water from in situ chemical leaching of uranium (Straz pod Ralskem, Czech Republic) was treated in laboratory scale experiments by zero-valent iron nanoparticles (nZVI). For the first time, nZVI were applied for the treatment of the real acid water system containing the miscellaneous mixture of pollutants, where the various removal mechanisms occur simultaneously. Toxicity of the treated saline acid water is caused by major contaminants represented by aluminum and sulphates in a high concentration, as well as by microcontaminants like As, Be, Cd, Cr, Cu, Ni, U, V, and Zn. Laboratory batch experiments proved a significant decrease in concentrations of all the monitored pollutants due to an increase in pH and a decrease in oxidation-reduction potential related to an application of nZVI. The assumed mechanisms of contaminants removal include precipitation of cations in a lower oxidation state, precipitation caused by a simple pH increase and co-precipitation with the formed iron oxyhydroxides. The possibility to control the reaction kinetics through the nature of the surface stabilizing shell (polymer vs. FeO nanolayer) is discussed as an important practical aspect.     

Toxicity of nanoparticulate and bulk ZnO, Al2O3 and TiO2 to the nematode Caenorhabditis elegans

Limited information is available on the environmental behavior and associated potential risk of manufactured oxide nanoparticles (NPs). In this research, toxicity of nanoparticulate and bulk ZnO, Al₂O₃ and TiO₂ were examined to the nematode Caenorhabditis elegans with Escherichia coli as a food source. Parallel experiments with dissolved metal ions from NPs were also conducted. The 24-h median lethal concentration (LC₅₀) and sublethal endpoints were assessed. Both NPs and their bulk counterparts were toxic, inhibiting growth and especially the reproductive capability of the nematode. The 24-h LC₅₀ for ZnO NPs (2.3 mg L⁻¹) and bulk ZnO was not significantly different, but significantly different between Al₂O₃ NPs (82 mg L⁻¹) and bulk Al₂O₃ (153 mg L⁻¹), and between TiO₂ NPs (80 mg L⁻¹) and bulk TiO₂ (136 mg L⁻¹). Oxide solubility influenced the toxicity of ZnO and Al₂O₃ NPs, but nanoparticle-dependent toxicity was indeed observed for the investigated NPs.     

Toxicity of TiO2, ZrO2, Fe,Fe2O3, and Mn2O3 nanoparticles to the yeast, Saccharomyces cerevisiae

The growing application of engineered nanomaterials is leading to an increased occurrence of nanoparticles (NPs) in the environment. Thus, there is a need to better understand their potential impact on the environment. This study evaluated the toxicity of nanosized TiO₂, ZrO₂, Fe⁰, Fe₂O₃, and Mn₂O₃ towards the yeast Saccharomyces cerevisiae based on O₂ consumption and cell membrane integrity. In addition, the state of dispersion of the nanoparticles in the bioassay medium was characterized.     

纳米金属对污水处理系统中磺胺耐药基因和耐药菌的影响及其机理

细菌耐药性和纳米材料污染为新兴环境问题。细菌耐药性遗传载体——耐药基因 (ARGs) 广泛存在于污水处理系统中,且已被证明与金属纳米材料密切相关。采用实时荧光定量PCR技术,探究了纳米零价铁 (nZVI) 和纳米氧化锌 (nZnO) 对污水处理系统中磺胺类耐药菌 (ARB) 和ARGs的分布特征的影响。结果表明,50 mg·L⁻¹ nZVI和nZnO暴露均有利于削减磺胺ARB浓度数。与对照组相比,nZVI和nZnO暴露后污泥中sul1丰度增加了0.25%~16.21%,而sul2出现明显削减 (1.51%~15.47%) 。此外,50 mg·L⁻¹ nZVI会导致游离态胞外ARGs大幅削减。nZVI和nZnO暴露通过富集污水处理系统中的intI1、改变细胞膜通透性和调节细菌转录能力促进sul1的增殖。本研究结果阐明了典型纳米金属对污水处理系统中ARB和不同形态ARGs消长的影响及其机制,可为制定有效调控和全面削减污水处理系统中耐药污染策略提供参考。     

Polymer coating of copper oxide nanoparticles increases nanoparticles uptake and toxicity in the green alga Chlamydomonas reinhardtii

Copper oxide nanoparticles (CuO NPs) are frequently used in a polymer-coated form, to be included in paints or fabrics for antimicrobial properties. Their application in antifouling paints may lead to the contamination of aquatic ecosystems. However, the toxicological risk of NPs in the environment is hard to evaluate due to a lack of knowledge on the mechanisms of NP interaction with biological systems. In this study, we investigated the effect of polymer coating on CuO NP toxicity in the green alga Chlamydomonas reinhardtii by comparing bare and polymer-coated CuO NPs prepared from the same CuO nanopowder. Both CuO NP suspensions were toxic to C. reinhardtii after 6 h treatment to concentrations of 0.005-0.04 g L⁻¹. Bare and polymer-coated CuO NPs induced a decrease of Photosystem II activity and the formation of reactive oxygen species. Polymer-coated CuO NP was found to be more toxic than the uncoated CuO NP. The higher toxicity of CS-CuO NP was mainly associated with the increased capacity of polymer-coated CuO NP to penetrate the cell compared to bare CuO NPs. These results indicates that the high toxicity of polymer-coated CuO NPs in algal cells results of intracellular interactions between NPs and the cellular system.