Dermal transfer and environmental release of CeO2 nanoparticles used as UV inhibitors on outdoor surfaces: Implications for human and environmental health

Indoor paint life cycle particle release: Safer-by-design products and the importance of choosing the right formula

In 2020, the European Commission published a regulation that states all producers of white paints containing titanium dioxide (TiO2) must provide a warning label on their products. Exposure during the production and application of products containing TiO2 can be harmful, and therefore these products must be labeled as "may cause cancer." The paint industry is a major user of TiO2 pigment. This study focuses on pigment release from three TiO2-based paints and discusses the effect of paint formulation, more precisely the Pigment Volume Concentration (PVC), to predict TiO2 pigment release from the paints during a simulated use phase and at the end of life (EoL). The use phase considered mild abrasion of painted panels that simulated cleaning or touching. The EoL phase was studied using leaching tests simulating landfill disposal. TiO2 release during both activities was evident with a high discrepancy between the three paints. While dry rubbing was similar for all paints, activities involving water present a high release link to paint matrix degradation. The paint pigment volume concentration and the paint permeability determines the TiO2 release during wet rubbing and leaching. This work represents an attempt to identify the paint permeability as a matrix-related parameter to predict TiO2 release and a way to use of this parameter to develop safer products.

Release of nanoparticle coatings additives from common surfaces via simulated dermal contact

Both nanoparticles (NPs) and nano-enabled products have become widely available in consumer markets in the last decade. Surface coating including paints, stains, and sealants, have seen large increases in the inclusion of nanomaterials in their formulations to increase UV resistance, hydrophobicity, and scratch resistance. Currently, most literature studying the release of NPs and byproducts from coated surfaces has focused exclusively on lumber. In this study, well characterized CeO2 NPs were dispersed in either Milli-Q water, or a commercial paint primer and applied to several test surfaces including sanded plywood, drywall, low density polyethylene, acrylonitrile butadiene styrene, polycarbonate, textured polycarbonate with pebble finish, and glass. Coated surfaces were sampled using a method previously developed by U.S. Consumer Product Safety Commission staff to track the release of NPs via simulated dermal contact. Particular attention has been paid to the total amount, and morphology of material released. The total amount of cerium released from coated surfaces was found to be dependent on both the identity of the test surface, as well as the solution used for coating. Water-based application found 22-50 % of the applied cerium removed during testing, while primer-based application showed released rates ranging between 0.1 and 3 %. Finally, the SEM micrographs presented here suggest the release of microplastic particles during simulated dermal contact with plastic surfaces.

Everything falls apart: How solids degrade and release nanomaterials, composite fragments, and microplastics

To ensure the safe use of materials, one must assess the identity and quantity of exposure. Solid materials, such as plastics, metals, coatings and cements, degrade to some extent during their life cycle, and releases can occur during manufacturing, use and end-of-life. Releases (e.g., what is released, how does release happen, and how much material is released) depend on the composition and internal (nano)structures of the material as well as the applied stresses during the lifecycle. We consider, in some depth, releases from mechanical, weathering and thermal stresses and specifically address the use cases of fused-filament 3D printing, dermal contact, food contact and textile washing. Solid materials can release embedded nanomaterials, composite fragments, or micro- and nanoplastics, as well as volatile organics, ions and dissolved organics. The identity of the release is often a heterogenous mixture and requires adapted strategies for sampling and analysis, with suitable quality control measures. Control materials enhance robustness by enabling comparative testing, but reference materials are not always available as yet. The quantity of releases is typically described by time-dependent rates that are modulated by the nature and intensity of the applied stress, the chemical identity of the polymer or other solid matrix, and the chemical identity and compatibility of embedded engineered nanomaterials (ENMs) or other additives. Standardization of methods and the documentation of metadata, including all the above descriptors of the tested material, applied stresses, sampling and analytics, are identified as important needs to advance the field and to generate robust, comparable assessments. In this regard, there are strong methodological synergies between the study of all solid materials, including the study of micro- and nanoplastics. From an outlook perspective, we review the hazard of the released entities, and show how this informs risk assessment. We also address the transfer of methods to related issues such as tyre wear, advanced materials and advanced manufacturing, biodegradable polymers, and non-solid matrices. As the consideration of released entities will become more routine in industry via lifecycle assessment in Safe-and-Sustainable-by-Design practices, release assessments will require careful design of the study with quality controls, the use of agreed-on test materials and standardized methods where these exist and the adoption of clearly defined data reporting practices that enable data reuse, meta-analyses, and comparative studies.

Improvement by application of three nanomaterials on flavor quality and physiological and antioxidant properties of tomato and their comparison

In recent years, it has been found that the flavor quality of tomato is continuously reduced compared with the original tomato varieties. Studies have found that nanomaterials can improve crop quality, but the differences and related mechanisms among different nanomaterials were not reported. In this study, nano-Se, nano-TiO2 and nano-CeO2 were spraying on tomato, and the effects of the three nanomaterials on the flavor quality and physiological and antioxidant properties of fruits were analyzed and compared. The results showed compared with nano-TiO2 and nano-CeO2, nano-Se showed more obvious positive effects. Nano-Se increased the size and weight of tomato fruits and the levels of soluble sugar, promoted the accumulation of photosynthetic pigment, decreased the content of titratable acid, and also changed the expression of related genes, finally making the fruit sweeter; it also promoted the accumulation of antioxidant substances and nutrients such as lycopene, ascorbic acid, salicylic acid, GSH, SOD and CAT and decreased the content of MDA, H2O2 and OFR thus improving the antioxidant performance of fruits; the contents of volatiles were also increased and the olfactory experience of tomato was improved. Nano-TiO2 and nano-CeO2 also improved the flavor quality and antioxidant properties of tomato, but the degree was lower than nano-Se. This experiment provided references for selecting more appropriate nanomaterials to improve tomato quality, and revealed the effects and mechanisms of different nanomaterials on tomato quality.

Size-resolved chemical composition and toxicity of particles released from refit operations in shipyards

Ship refit and repair operations in shipyards generate aerosol emissions with high potential for environmental impacts. Metal-bearing nano-, fine and coarse particles are incidentally formed and can be released to indoor and ambient air and the aquatic environment. This work aimed to further the understanding of these impacts by characterising particle size-resolved chemical composition (15 nm - 10 μm), organophosphate esters (OPEs) content (e.g., plasticisers) and cytotoxic and genotoxic potential. Results showed that nanoparticle emissions (20-110 nm) took place in bursts, coinciding with the use of mechanical abraders and spray-painting guns. Tracers of these activities were Sc, V, Cr, Co, Ni, Cu, Rb, Nb, and Cs. Key components were V and Cu, probably sourcing from nanoadditives in the coatings. Abrasion of coatings also emitted OPEs, especially from old paints. Toxicity assessments consistently evidenced hazardous potential for the different endpoints assessed, for a number of samples. Exposures to spray-painting aerosols were linked with reduced cell viability (cytotoxicity), significant generation of reactive oxygen species (ROS), and increases in micronuclei frequency (genotoxicity). Even though spray-painting did not contribute significantly to aerosol mass or number concentrations, it was a major driver of potential health effects. Results suggest that aerosol chemical composition (e.g., content in nano-sized Cu or V) may have a larger impact on toxicity than aerosol concentration. While direct human exposures may be prevented using personal and collective protective equipment and environmental release can be minimised by enclosures and filtration systems, impacts on ambient air and the aquatic environment cannot be fully prevented. The continued use of good practices (exhaust, dilution, general ventilation systems, PPE, already in place) is encouraged to reduce inhalation exposures inside the tents. Understanding the size-resolved chemical and toxicological properties of aerosols is key to reducing human health and environmental impacts of ship refit operations in shipyards.

Transformation of zinc oxide nanoparticles in synthetic lung fluids

Surface coatings, including paints, stains, and sealants, have recently become a focus of "nano-enabled" consumer product engineering. Specifically, zinc oxide (ZnO) nanoparticles (NPs) have been introduced to surface coatings to increase UV resistance. As more "nano-enabled" products are made available for purchase, questions arise regarding their long-term environmental and human health effects. This study tracked the transformation of NP additives commonly added to consumer paints and stains using ZnO NPs as a model system. During product application and use, there is a risk of inhalation of aerosolized ZnO NPs. To investigate the potential chemical interactions and transformations that would occur after inhalation, ZnO NPs were incubated in two synthetic lung fluids (SLFs). Initial studies utilized ZnO NPs dispersed in Milli-Q water (control), or a commercially available deck stain. Additionally, two commercially available products advertising the inclusion of ZnO NP additives were evaluated. Subsamples were taken throughout incubation and analyzed via atomic absorption spectroscopy to determine both the total (including particulate) zinc concentration and dissolved (non-particulate) zinc concentration. Results indicate that the vast majority of ZnO transformation takes place within the first 24 h of incubation and is primarily driven by SLF pH and composition complexity. Significant dissolution of ZnO NPs was observed when incubated in Gamble's solution (between 25 and 68% depending on the matrix. Additionally, all ZnO solutions saw near immediate dissolution (~ 98-100%) within 3 h of incubation in artificial lysosomal fluid. Results illustrate potential for NPs in consumer products to undergo significant transformation during use and exposure over short time periods.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11051-022-05527-y.

An integrated ICP-MS-based analytical approach to fractionate and characterize ionic and nanoparticulate Ce species

Cerium dioxide nanoparticles (CeO₂ NPs) are widely used in various fields, leading to concern about their effect on human health. When conducting in vivo investigations of CeO₂ NPs, the challenge is to fractionate ionic Ce and CeO₂ NPs and to characterize CeO₂ NPs without changing their properties/state. To meet this challenge, we developed an integrated inductively coupled plasma-mass spectrometry (ICP-MS)-based analytical approach in which ultrafiltration is used to fractionate ionic and nanoparticulate Ce species while CeO₂ NPs are characterized by single particle-ICP-MS (sp-ICP-MS). We used this technique to compare the effects of two sample pretreatment methods, alkaline and enzymatic pretreatments, on ionic Ce and CeO₂ NPs. Results showed that enzymatic pretreatment was more efficient in extracting ionic Ce or CeO₂ NPs from animal tissues. Moreover, results further showed that the properties/states of all ionic and nanoparticulate Ce species were well preserved. The rates of recovery of both species were over 85%; the size distribution of CeO₂ NPs was comparable to that of original NPs. We then applied this analytical approach, including the enzymatic pretreatment and ICP-MS-based analytical techniques, to investigate the bioaccumulation and biotransformation of CeO₂ NPs in mice. It was found that the thymus acts as a "holding station" in CeO₂ NP translocation in vivo. CeO₂ NP biotransformation was reported to be organ-specific. This is the first study to evaluate the impact of enzymatic and alkaline pretreatment on Ce species, namely ionic Ce and CeO₂ NPs. This integrated ICP-MS-based analytical approach enables us to conduct in vivo biotransformation investigations of CeO₂ NPs.

Particle release from refit operations in shipyards: Exposure, toxicity and environmental implications

European harbours are known to contribute to air quality degradation. While most of the literature focuses on emissions from stacks or logistics operations, ship refit and repair activities are also relevant aerosol sources in EU harbour areas. Main activities include abrasive removal of filler and spray painting with antifouling coatings/primers/topcoats. This work aimed to assess ultrafine particle (UFP) emissions from ship maintenance activities and their links with exposure, toxicity and health risks for humans and the aquatic environment. Aerosol emissions were monitored during mechanical abrasion of surface coatings under real-world operating conditions in two scenarios in the Mallorca harbour (Spain). Different types of UFPs were observed: (1) highly regular (triangular, hexagonal) engineered nanoparticles (Ti-, Zr-, Fe-based), embedded as nano-additives in the coatings, and (2) irregular, incidental particles emitted directly or formed during abrasion. Particle number concentrations monitored were in the range of industrial activities such as drilling or welding (up to 5 ∗ 10⁵/cm³, mean diameters <30 nm). The chemical composition of PM₄ aerosols was dominated by metallic tracers in the coatings (Ti, Al, Ba, Zn). In vitro toxicity of PM₂ aerosols evidenced reduced cell viability and a moderate potential for cytotoxic effects. While best practices (exhaust ventilation, personal protective equipment, dust removal) were in place, it is unlikely that exposures and environmental release can be fully avoided at all times. Thus, it is advisable that health and safety protocols should be comprehensive to minimise exposures in all types of locations (near- and far-field) and periods (activity and non-activity). Potential release to coastal surface waters of metallic engineered and incidental nanomaterials, as well as fine and coarse particles (in the case of settled dust), should be assessed and avoided.

Variation in zinc release from surface coatings as a function of methodology

Over the last decade the growth of "nano-enabled" products have exploded in both industrial and direct to consumer applications. One area of interest is surface coatings, including paints, stains and sealants. Large scale applications of the products raise questions about both short- and long-term effects to both human and environmental health. Release of nanoparticles (NPs) from surfaces as a function of dermal contact is recognized as a potential human exposure route. Several standardized methods to quantify nanomaterial release have been previously used. In the current study, two standardized method were used to quantify the total mass of NPs released during sampling. ZnO (NPs) were used as a case study as they are commonly added to surface coatings to increase UV resistance. Particles were dispersed in Milli-Q water or a deck stain and applied to sanded plywood surfaces. Total release of Zn due to simulated dermal contact was evaluated using the Consumer Product Safety Commission (CPSC) and National Institute for Occupational Safety and Health (NIOSH) wipe methods. Additionally, three different sampling materials were tested. The total quantity of Zn released between the two methods was dependent upon the material used and how the ZnO was applied to the surface. Critically, less than 3% of the ZnO NPs applied to test surfaces was removed using either method. The results of this study demonstrate how different testing methodologies may result in varying estimates of human and environmental risk from NPs in surface coatings.

Oil in Water Nanoemulsions Loaded with Tebuconazole for Populus Wood Protection against White- and Brown-Rot Fungi

Eugenol in water nanoemulsions loaded with tebuconazole appear as a very promising alternative formulations for wood protection against xylophagous fungi that are the main species responsible for different rots in wood structures. The dispersions as prepared and upon dilution (impregnation mixtures) were characterized by the apparent hydrodynamic diameter distribution of the oil droplets loaded with tebuconazole and their long-term stability. The impregnation mixtures were applied on wood of Populus canadensis I-214 clone by using a pressure-vacuum system, and the effectiveness against fungal degradation by Gloeophyllum sepiarium and Pycnoporus sanguineus fungi was determined. The retention of tebuconazole in wood was about 40% of the amount contained in the impregnation mixtures. The results showed that the impregnation process leads to a long-term antifungal protection to the wood, with the mass loss after 16 weeks being reduced more than 10 times in relation to the control (untreated poplar wood) and the reference wood (untreated beech wood).

Measurement of CeO2 Nanoparticles in Natural Waters Using a High Sensitivity, Single Particle ICP-MS

As the production and use of cerium oxide nanoparticles (CeO₂ NPs) increases, so does the concern of the scientific community over their release into the environment. Single particle inductively coupled plasma mass spectrometry is emerging as one of the best techniques for NP detection and quantification; however, it is often limited by high size detection limits (SDL). To that end, a high sensitivity sector field ICP-MS (SF-ICP-MS) with microsecond dwell times (50 µs) was used to lower the SDL of CeO₂ NPs to below 4.0 nm. Ag and Au NPs were also analyzed for reference. SF-ICP-MS was then used to detect CeO₂ NPs in a Montreal rainwater at a concentration of (2.2 ± 0.1) × 10⁸ L⁻¹ with a mean diameter of 10.8 ± 0.2 nm; and in a St. Lawrence River water at a concentration of ((1.6 ± 0.3) × 10⁹ L⁻¹) with a higher mean diameter (21.9 ± 0.8 nm). SF-ICP-MS and single particle time of flight ICP-MS on Ce and La indicated that 36% of the Ce-containing NPs detected in Montreal rainwater were engineered Ce NPs.

Release and transformation of nanoparticle additives from surface coatings on pristine & weathered pressure treated lumber

As the market for "nano-enabled" products (NEPs) continues to expand in commercial and industrial applications, there is a critical need to understand conditions that promote release of nanomaterials and their degradation products from NEPs. Moreover, these studies must aim to quantify both the abundance and form (aggregates, ions, hybrids, etc.) of material released from NEPs to produce reasonable estimates of human and environmental exposure. In this work ZnO nanoparticles (NPs), a common additive in NEP surface coatings, were dispersed in Milli-Q water and a commercially available wood stain before application to pristine and weathered (outdoor 1 year) micronized copper azole pressure treated lumber (MCA). Coated lumber surfaces were sampled consecutively eight times using a method developed by the Consumer Product Safety Commission (CPSC) to track potential human exposure to ZnO NPs and byproducts through simulated dermal contact. Surprisingly, the highest total release of Zn was observed from aged lumber coated with ZnO NPs dispersed in wood stain, releasing 233 ± 26 mg Zn/m² over the course of all sampling events. Alternatively, separate leaching experiments using a synthetic precipitation solution to simulate environmental release found aged lumber released significantly less Zn than pristine lumber when using the same coating formulation. Zinc speciation analysis also demonstrates that transformation of crystalline ZnO to Zn-organic complexes shortly after application to aged lumber. Regardless of experimental treatment, the majority of applied zinc (>75%) remains on the MCA surface. Finally, this work highlights how the nature of the screening technique (dermal contact vs. leaching) may result in different interpretations of exposure and risk.

Environmental effects of stratospheric ozone depletion, UV radiation and interactions with climate change: UNEP Environmental Effects Assessment Panel, update 2019

This assessment, by the United Nations Environment Programme (UNEP) Environmental Effects Assessment Panel (EEAP), one of three Panels informing the Parties to the Montreal Protocol, provides an update, since our previous extensive assessment (Photochem. Photobiol. Sci., 2019, 18, 595-828), of recent findings of current and projected interactive environmental effects of ultraviolet (UV) radiation, stratospheric ozone, and climate change. These effects include those on human health, air quality, terrestrial and aquatic ecosystems, biogeochemical cycles, and materials used in construction and other services. The present update evaluates further evidence of the consequences of human activity on climate change that are altering the exposure of organisms and ecosystems to UV radiation. This in turn reveals the interactive effects of many climate change factors with UV radiation that have implications for the atmosphere, feedbacks, contaminant fate and transport, organismal responses, and many outdoor materials including plastics, wood, and fabrics. The universal ratification of the Montreal Protocol, signed by 197 countries, has led to the regulation and phase-out of chemicals that deplete the stratospheric ozone layer. Although this treaty has had unprecedented success in protecting the ozone layer, and hence all life on Earth from damaging UV radiation, it is also making a substantial contribution to reducing climate warming because many of the chemicals under this treaty are greenhouse gases.

Size and Surface Charge Dependent Impregnation of Nanoparticles in Soft- and Hardwood

Recent progress in wood preservative research has led to the use of insoluble copper carbonate in the form of nano- to micron-sized particles in combination with known triazole fungicides to combat fungal decay and thus decrease physical material properties. Evidently, particle-based agents could lead to issues regarding impregnation of a micro-structured material like wood. In this study, we analyzed these limitations via silicon dioxide particles in impregnation experiments of pine and beech wood. In our experiments, we showed that limitations already existed prior to assumed particle size thresholds of 400–600 nm. In pine wood, 70 nm sized particles were efficiently impregnated, in contrast to 170 nm particles. Further we showed that surface functionalized silica nanoparticles have a major impact on the impregnation efficiency. Silica surfaces bearing amino groups were shown to have strong interactions with the wood cell surface, whereas pentyl chains on the SiO2 surfaces tended to lower the particle–wood interaction. The acquired results illustrate an important extension of the currently limited knowledge of nanoparticles and wood impregnation and contribute to future improvements in the field of particle-based wood preservatives.

Transformation and release of nanoparticle additives & byproducts from commercially available surface coatings on pressure treated lumber via dermal contact

Production and marketing of "nano-enabled" products for consumer purchase has continued to expand. However, many questions remain about the potential release and transformation of these nanoparticle (NP) additives from products throughout their lifecycle. In this work, two surface coating products advertised as containing ZnO NPs as active ingredients, were applied to micronized copper azol (MCA) and aqueous copper azol (ACA) pressure treated lumber. Coated lumber was weathered outdoors for a period of six months and the surface was sampled using a method developed by the Consumer Product Safety Commission (CPSC) to track potential human exposure to ZnO NPs and byproducts through simulated dermal contact. Using this method, the total amount of zinc extracted during a single sampling event was <1 mg/m² and no evidence of free ZnO NPs was found. Approximately 0.5% of applied zinc was removed via simulated dermal contact over 6-months, with increased weathering periods resulting in increased zinc release. XAFS analysis found that only 27% of the zinc in the as received coating could be described as crystalline ZnO and highlights the transformation of these mineral phases to organically bound zinc complexes during the six-month weathering period. Additionally, SEM images collected after sampling found no evidence of free NP ZnO release during simulated dermal contact. Both simulated dermal contact experiments, and separate leaching studies demonstrate the application of surface coating solutions to either MCA and ACA lumber will reduce the release of copper from the pressure treated lumber. This work provides clear evidence of the transformation of NP additives in consumer products during their use stage.

Cerium Oxide Nanoparticles Absorption through Intact and Damaged Human Skin

Cerium oxide (CeO2) nanoparticles (NPs) are used in polishing products and absorbents, as promoters in wound healing, and as organopesticide decontaminants. While systemic bioaccumulation and organ toxicity has been described after inhalation, data on CeO2 NPs' transdermal permeation are lacking. Our study was an in vitro investigation of the permeation of 17-nm CeO2 NPs dispersed in synthetic sweat (1 g L-1) using excised human skin on Franz cells. Experiments were performed using intact and needle-abraded skin, separately. The average amount of Ce into intact and damaged skin samples was 3.64 ± 0.15 and 7.07 ± 0.78 µg cm-2, respectively (mean ± SD, p = 0.04). Ce concentration in the receiving solution was 2.0 ± 0.4 and 3.3 ± 0.7 ng cm-2 after 24 h (p = 0.008). The Ce content was higher in dermal layers of damaged skin compared to intact skin (2.93 ± 0.71 µg cm-2 and 0.39 ± 0.16 µg cm-2, respectively; p = 0.004). Our data showed a very low dermal absorption and transdermal permeation of cerium, providing a first indication of Ce skin uptake due to contact with CeO2.

Release and transformation of ZnO nanoparticles used in outdoor surface coatings for UV protection

A major area of growth for "nano-enabled" products has been the addition of nanoparticles (NPs) to surface coatings including paints, stains and sealants. Zinc oxide (ZnO) NPs, long used in sunscreens and sunblocks, have found growing use in surface coating formulations to increase their UV resistance, especially on outdoor products. In this work, ZnO NPs, marketed as an additive to paints and stains, were dispersed in Milli-Q water and a commercial deck stain. Resulting solutions were applied to either Micronized-Copper Azole (MCA) pressure treated lumber or a commercially available composite decking. A portion of coated surfaces were placed outdoors to undergo environmental weathering, while the remaining samples were stored indoors to function as experimental controls. Weathered and control treatments were subsequently sampled periodically for 6 months using a simulated dermal contact method developed by the Consumer Product Safety Commission (CPSC). The release of ZnO NPs, and their associated degradation products, was determined through sequential filtration, atomic spectroscopy, X-Ray Absorption Fine Structure Spectroscopy, and electron microscopy. Across all treatments, the percentage of applied zinc released through simulated dermal contact did not exceed 4%, although transformation and release of zinc was highly dependent on dispersion medium. For MCA samples weathered outdoors, water-based applications released significantly more zinc than stain-based, 180 ± 28, and 65 ± 9 mg/m² respectively. Moreover, results indicate that the number of contact events drives material release.

Determination of Nanoparticle Uptake, Distribution, and Characterization in Plant Root Tissue after Realistic Long-Term Exposure to Sewage Sludge Using Information from Mass Spectrometry

The use of nanoparticles (NPs) in numerous products and their potential accumulation causes major concern for humans and the environment. Until now, the uptake of NPs in plant tissue was mostly shown under greenhouse conditions at high doses and short exposure periods. Here, we present results on the uptake of particulate silver (Ag) and cerium dioxide (CeO₂) in the tissues of Triticum aestivum, Brassica napus, and Hordeum vulgare, after exposure to sewage sludge treated with nano-Ag (NM300 K at 1.8 and 7.0 mg/kg sludge per dm soil) and nano-CeO₂ (NM212 at 10 and 50 mg/kg sludge per dm soil). All plants were cultivated in a rural area near the German town Schmallenberg according to the common regional crop rotation on outdoor lysimeters. The highest concentrations measured were 86.4 mg/kg for Ag ( Hordeum vulgare) and 94 mg/kg for Ce ( Triticum sativum). Analysis of plant samples revealed the presence of Ag mainly in its ionic form. However, the occurrence of nano- and larger sized particles of Ag and CeO₂ was observed as well. Quantitative shares of the particulate fraction of the total element concentration were estimated up to 22.4% for Ag and up to 85.1% for CeO₂. A high abundance of particle agglomerates in the phloem suggests upward transport of the nanoparticles to other plant parts. A small number of agglomerates in the xylem suggests a downward transport and subsequent accumulation in the root phloem. Exemplary investigations of Brassica napus root exposed to nano-CeO₂ revealed no accumulation of the pristine material in the cell nucleus; however, CePO₄ was found_. The presence of this substance points to a dissolution of the low soluble CeO₂ in planta and subsequent precipitation. Furthermore, for the first time, mixed NP-salt agglomerates, composed of Ca₃PO₄⁺ and K₃SO₄⁺ NPs, could be observed within Brassica napus root tissue.

Electrospun silica nanofiber mats functionalized with ceria nanoparticles for water decontamination

This study demonstrates the fabrication of nanoceria-immobilized silica nanofibers for efficient water decontamination with easy reuse and regeneration properties.

Interactive effects of solar UV radiation and climate change on material damage

Solar UV radiation adversely affects the properties of organic materials used in construction, such as plastics and wood.