Environmental Science: Nano

Journal: Environmental Science: Nano

Abbreviation

Environ. Sci., Nano

Publisher

Royal Society of Chemistry

ISSN

2051-8161
2051-8153

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Publications1 - 10 of 45

Effect of humic acid on the kinetics of silver nanoparticle sulfidation
Thalmann, Basilius; Voegelin, Andreas; Morgenroth, Eberhard; et al. (2016)
Environmental Science: Nano
Release of gold (Au), silver (Ag) and cerium dioxide (CeO2) nanoparticles from sewage sludge incineration ash
Wielinski, Jonas; Gogos, Alexander; Voegelin, Andreas; et al. (2021)
Environmental Science: Nano
Engineered nanoparticles (NPs) that are released into wastewater are retained by wastewater treatment plants (WWTPs) and accumulate in sewage sludge. Increasing shares of sludge are incinerated and landfilled, especially in industrialized countries. It is debated whether certain types of NPs can outlive the incineration process and subsequently be released from sewage sludge ash (SSA) landfills. To investigate the release of different types of NPs from SSA, we spiked gold (Au), silver (Ag) and cerium dioxide (CeO2) NPs to a pilot WWTP increasing the Au, Ag and Ce concentrations to 30, 43 and 389 mg kg−1 (dry matter basis) in the digested sludge. The spiked sludge was incinerated in a pilot fluidized bed reactor resulting in SSA with Au, Ag and Ce concentrations of 61, 103 and 854 mg kg−1. In addition, two sludge samples from a full-scale WWTP with Au concentrations of 5 and 16 mg kg−1 were incinerated, resulting in SSA with 9 mg kg−1 and 30 mg kg−1 Au. The spiked Au-NPs remain largely unaltered during the wastewater treatment and incineration process, whereas Ag-NPs and CeO2-NPs undergo transformation. During simulated landfill leaching in columns flushed with 400 to 500 pore volumes of artificial rainwater, Ag and Ce were retained in the ash, whereas about 17% of the spiked Au was released, mainly in particulate form. Lower fractions of mostly particulate Au were released from the ashes (3 and 9%) of unspiked SSA. In conclusion, unaltered Au-NPs significantly leach from landfilled SSA, whereas the incorporation of Ag-NPs and CeO2-NPs as transformed species into the SSA matrix limits the leaching of (nano)particulate and dissolved Ag and Ce compounds.
Prediction of nanoparticle transport behavior from physicochemical properties: machine learning provides insights to guide the next generation of transport models
Goldberg, Eli; Scheringer, Martin; Bucheli, Thomas; et al. (2015)
Environmental Science: Nano
In the last 15 years, the development of advection–dispersion particle transport models (PTMs) for the transport of nanoparticles in porous media has focused on improving the fit of model results to experimental data by inclusion of empirical parameters. However, the use of these PTMs has done little to elucidate the complex behavior of nanoparticles in porous media and has failed to provide the mechanistic insights necessary to predictively model nanoparticle transport. The most prominent weakness of current PTMs stems from their inability to consider the influence of physicochemical conditions of the experiments on the transport of nanoparticles in porous media. Qualitative physicochemical influences on particle transport have been well studied and, in some cases, provide plausible explanations for some aspects of nanoparticle transport behavior. However, quantitative models that consider these influences have not yet been developed. With the current work, we intend to support the development of future mechanistic models by relating the physicochemical conditions of the experiments to the experimental outcome using ensemble machine learning (random forest) regression and classification. Regression results demonstrate that the fraction of nanoparticle mass retained over the column length (retained fraction, RF; a measure of nanoparticle transport) can be predicted with an expected mean squared error between 0.025–0.033. Additionally, we find that RF prediction was insensitive to nanomaterial type and that features such as concentration of natural organic matter, ζ potential of nanoparticles and collectors and the ionic strength and pH of the dispersion are strongly associated with the prediction of RF and should be targets for incorporation into mechanistic models. Classification results demonstrate that the shape of the retention profile (RP), such as hyperexponential or linearly decreasing, can be predicted with an expected F1-score between 60–70%. This relatively low performance in the prediction of the RP shape is most likely caused by the limited data on retention profile shapes that are currently available.
Silver nanoparticle–protein interactions in intact rainbow trout gill cells
Yue, Yang; Behra, Renata; Sigg, Laura; et al. (2016)
Environmental Science: Nano
Upon contact with biota, nanoparticles can bind to proteins, which coat the nanoparticles and form a nanoparticle-protein corona. Knowledge of corona proteins is therefore important for a mechanistic understanding of how nanoparticles interact with biomolecules in cells. Here we present the first study to reveal the identity of corona proteins from silver nanoparticle (AgNPs)-exposed living vertebrate cells. The cells are from a rainbow trout (Oncorhynchus mykiss) gill cell line, RTgill-W1, representing the interface between the aquatic environment and one of its model species. Subcellular fractionation allowed AgNP-protein corona complexes to be recovered from intact subcellular compartments and proteins lysed from the AgNPs to be detected by mass spectrometry. The identified proteins mark the trail of AgNPs processing in the cells like a forensic fingerprint: the cells take up the AgNPs via endocytic processes and store the particles in endosomal/lysosomal compartments. Moreover, stress response proteins were recovered in the AgNPs protein corona. In this way, we established a list of AgNPs susceptible proteins which can be investigated further in targeted nanoparticle–protein interaction. As a proof of principle, we demonstrate that Na+/K+-ATPase, identified from the corona and a known key protein in ion regulation in gill cells, is inhibited in its activity by AgNPs, confirming previously published in vivo experiments. The developed methodology is broadly applicable to other nanoparticles and cell types, representing a valuable tool for mechanistic nanoparticle–cell interaction studies, ranging from environmental and human risk assessment to biomedicine. In this way, our research also contributes to safer particle design.
Organic matter influences transformation products of ferrihydrite exposed to sulfide
Thomas Arrigo, Laurel K.; Bouchet, Sylvain; Kaegi, Ralf; et al. (2020)
Environmental Science: Nano
In redox-dynamic environments, sorption to poorly-crystalline, nanometer-sized Fe(III)-(oxyhydr)oxides like ferrihydrite influences the biogeochemical cycling of nutrients and trace elements. Under sulfate-reducing conditions, the reductive dissolution of ferrihydrite leads to the release of associated constituents, which may be re-immobilized via sorption to secondary Fe minerals. To date, studies following the kinetics and transformation pathways of Fe(III)-(oxyhydr)oxides upon exposure to dissolved sulfide (S(−II)) have largely focused on pure Fe minerals. However, in nature, Fe(III)-(oxyhydr)oxides are often found in association with organic matter (OM). Because ferrihydrite–OM associations exhibit characteristics and biogeochemical reactivity differing from those of pure ferrihydrite, in this study, we compared sulfidization kinetics and transformation pathways of a pure ferrihydrite to those of ferrihydrite coprecipitated with contrasting organic ligands; polygalacturonic acid, galacturonic acid, and citric acid (C/Fe molar ratio ∼0.55). Incorporating aqueous- and solid-phase S and Fe speciation analyses (via wet chemistry techniques and S and Fe X-ray absorption spectroscopy) in addition to X-ray diffraction and electron microscopy, we studied both rapid (<7 days) and long-term (12 months) mineral transformations as well as the impact of varying S(−II)/Fe molar ratios at neutral pH. Our results showed that at low S(−II)/Fe molar ratios (=0.1), poorly-crystalline Fe sulfide minerals (e.g. mackinawite) did not form in any (co)precipitate. In contrast, at higher S(−II)/Fe molar ratios (=0.5), mackinawite rapidly precipitated, with higher contributions detected in the coprecipitates than in the pure ferrihydrite. Aging of the samples led to further mineral transformations, including divergent pyrite and greigite precipitation, and an overall increase in the crystallinity of secondary mineral phases. Still, the fraction of residual ferrihydrite at 12 months was higher in the OM-containing coprecipitates, with the most ferrihydrite preservation observed in coprecipitates comprising carboxyl-poor ligands (galacturonic acid and citric acid). This suggests that the presence of OM inhibited S(−II)-induced ferrihydrite mineral transformations and that the composition of the associated OM influenced mineral transformation pathways. Collectively, these results suggest that further studies regarding sulfidization pathways should include OM in order to better represent environmental conditions.
Environmentally relevant UV-light weathering of polystyrene micro- and nanoplastics promotes hepatotoxicity in a human cell line
Englert, Felix H.; Mueller, Fabrice A.; Dugershaw-Kurzer, Battuja; et al. (2023)
Environmental Science: Nano
Background: micro- and nanoplastics (MPs/NPs) are global pollutants of concern to human health due to their increasing environmental accumulation and biopersistence. They can reach systemic circulation and distribute to organs, with the liver being a potential target due to its propensity to accumulate particles. However, knowledge of MP and NP hepatotoxicity is scarce and mostly focused on primary particles, which lack environmental relevance. Therefore, the aim of this study was to characterize how UV-weathering influences hepatic cell responses to polystyrene (PS) MPs and NPs. Results: we characterized the effects of primary PS MPs (3 mu m) and NPs (25 and 100 nm) on a human liver cell line (HepaRG) by using high content imaging to profile alterations in pathologically relevant key cellular events, including oxidative stress, lipid accumulation, and nuclear morphology, as well as evaluating differential expression of genes relevant to lipid metabolism, inflammation, and carcinogenesis. We observed no changes in cell viability even at high concentrations (100 mu g ml(-1)) or after prolonged exposure (10 days). However, after UV-induced weathering, PS particles induced cytotoxicity after 24 h at a concentration of 0.1 mu g ml(-1), which is <7% of PS particle concentrations detected in human blood. Other cellular stress responses were observed only upon exposure concentrations of UV-weathered particles more than four times the maximum concentration (12 mu g ml(-1)) detected in human blood. Finally, genes involved in lipid metabolism, inflammation, and carcinogenesis were upregulated upon exposure to most of the tested MPs and NPs. Conclusions: UV-weathering of pristine PS MPs and NPs increases their hepatotoxicity. Cytotoxicity was more pronounced for micro-sized PS particles, but PS NPs induced the expression of genes relevant to the development or progression of fatty liver disease. The data demonstrate the relevance of accounting for effects of weathering on the properties and biological impacts of MPs and NPs and emphasize the need for further studies of chronic MP and NP exposure on tissue function and disease risk.
Toxicity and translocation of Ag, CuO, ZnO and TiO2 nanoparticles upon exposure to fish intestinal epithelial cells
Geppert, Mark; Sigg, Laura; Schirmer, Kristin (2021)
Environmental Science: Nano
Understanding the ability of fish intestinal cells to act as a barrier for nanoparticle (NP) uptake and their effects is of significance from an environmental perspective as well as for human health, for which fish serves as an important nutrient source. We used an in vitro intestinal barrier model, based on rainbow trout intestinal (RTgutGC) cells, to elaborate the toxicity and translocation of five types of metal-based NPs. The NPs were polyvinylpyrrolidone (PVP)-coated Ag NPs, uncoated Ag NPs, CuO NPs, ZnO NPs and TiO2 NPs. In conventional monolayers on impermeable supports, cell viability declined according to classical sigmoidal dose–response curves with EC50 values between 0.28 mg L−1 and >100 mg L−1 in the following rank order, from the most toxic (lowest EC50) to the least toxic (highest EC50): PVP–Ag NPs < uncoated Ag NPs < CuO NPs < ZnO NPs < TiO2 NPs. When cells were cultured on permeable membranes to mimic an intestinal lumen and a blood-facing side, however, a much higher resistance of the cells towards NP-induced stress was noted with little to no impact on cell viability or barrier integrity. Yet, increased levels of Ag, Cu and Zn but not Ti were measured in the blood-side mimicking (basolateral) compartment, indicating translocation of Ag, Cu, and Zn-based NPs or ions liberated from them through the epithelial cell layer. Since especially CuO NPs appeared to be translocated as intact particles, they were investigated in more detail. A time- and temperature-dependent analysis, involving different endocytosis inhibitors, suggested that CuO NPs were translocated through the epithelium by apical caveolae-mediated endocytosis followed by delayed export onto the basolateral side. These data give valuable insights into NP uptake by, and translocation through, the fish intestinal epithelium and will be of value for future research on the molecular mechanisms of NPs that enter the fish via this critical uptake route.
Emerging investigator series: automated single-nanoparticle quantification and classification: a holistic study of particles into and out of wastewater treatment plants in Switzerland
Mehrabi, Kamyar; Kaegi, Ralf; Günther, Detlef; et al. (2021)
Environmental Science: Nano
Single particle inductively coupled plasma time-of-flight mass spectrometry (sp-ICP-TOFMS), in combination with online microdroplet calibration, allows for the determination of particle number concentrations (PNCs) and the amount (i.e. mass) of ICP-MS-accessible elements in individual particles. Because sp-ICP-TOFMS analyses of environmental samples produce rich datasets composed of both single-metal nanoparticles (smNPs) and many types of multi-metal NPs (mmNPs), interpretation of these data is well suited to automated analysis schemes. Here, we present a new data analysis approach that includes: 1. automatic particle detection and elemental mass determinations based on online microdroplet calibration, 2. correction of false (randomly occurring) multi-metal associations caused by measurement of coincident but distinct NPs, and 3. unsupervised clustering analysis of mmNPs to identify unique classes of NPs based on their element compositions. To demonstrate the potential of our approach, we analyzed water samples collected from the influent and effluent of five wastewater treatment plants (WWTPs) across Switzerland. We determined elemental masses in individual NPs, as well as PNCs, to estimate the NP removal efficiencies of the individual WWTPs. From WWTP samples collected at two points in time, we found an average of 90% and 94% removal efficiencies of single-metal and multi-metal NPs, respectively. Between 5% to 27% of detected NPs were multi-metal; the most abundant particle types were those rich in Ce–La, Fe–Al, Ti–Zr, and Zn–Cu. Through hierarchical clustering, we identified NP classes conserved across all WWTPs, as well as particle types that are unique to one or a few WWTPs. These uniquely occurring particle types may represent point sources of anthropogenic NPs. We describe the utility of clustering analysis of mmNPs for identifying natural, geogenic NPs, and also for the discovery of new, potentially anthropogenic, NP targets.
Metal-doping of nanoplastics enables accurate assessment of uptake and effects on Gammarus pulex
Redondo-Hasselerharm, Paulo E.; Vink, Gerko; Mitrano, Denise Marie; et al. (2021)
Environmental Science: Nano
Because of the difficulty of measuring nanoplastics (NP), the use of NPs doped with trace metals has been proposed as a promising approach to detect NP in environmental media and biota. In the present study, the freshwater amphipod Gammarus pulex were exposed to palladium (Pd)-doped NP via natural sediment at six spiking concentrations (0, 0.3, 1, 3, 10 and 30 g plastic per kg of sediment dry weight) with the aim of assessing their uptake and chronic effects using 28 days standardized single species toxicity tests. NP concentrations were quantified based on Pd concentrations measured by ICP-MS on digests of the exposed organisms and faecal pellets excreted during a post-exposure 24 hour depuration period. Additionally, NP concentrations were measured in sediments and water to demonstrate accuracy of NP dosing and to quantify the resuspension of NP from the sediment caused by the organisms. A significant positive linear relationship between the uptake of NP by G. pulex and the concentration of NP in the sediments was observed, yet no statistically significant effects were found on the survival or growth of G. pulex. A biodynamic model fitted well to the data and suggested bioaccumulation would occur in two kinetic compartments, the major one being reversible with rapid depuration to clean medium. Model fitting yielded a mass based trophic transfer factor (TTF), conceptually similar to the traditional biota sediment accumulation factor, for NP in the gut of 0.031. This value is close to a TTF value of 0.025 that was obtained for much larger microplastic particles in a similar experiment performed previously. Mechanistically, this suggests that ingestion of plastic is limited by the total volume of ingested particles. We demonstrated that using metal-doped plastics provides opportunities for precise quantification of NP accumulation and exposure in fate and effect studies, which can be a clear benefit for NP risk assessment.
Offering authors a choice: Introduction of optional double-blind peer review
McNeill, Kristopher; Novak, Paige J.; Vikesland, Peter J. (2020)
Environmental Science: Nano

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