Wildfire Ashes from the Wildland-Urban Interface Alter Vibrio vulnificus Growth and Gene Expression.

Climate change-induced stressors are contributing to the emergence of infectious diseases, including those caused by marine bacterial pathogens such as Vibrio spp. These stressors alter Vibrio temporal and geographical distribution, resulting in increased spread, exposure, and infection rates, thus facilitating greater Vibrio-human interactions. Concurrently, wildfires are increasing in size, severity, frequency, and spread in the built environment due to climate change, resulting in the emission of contaminants of emerging concern. This study aimed to understand the potential effects of urban interface wildfire ashes on Vibrio vulnificus (V. vulnificus) growth and gene expression using transcriptomic approaches. V. vulnificus was exposed to structural and vegetation ashes and analyzed to identify differentially expressed genes using the HTSeq-DESeq2 strategy. Exposure to wildfire ash altered V. vulnificus growth and gene expression, depending on the trace metal composition of the ash. The high Fe content of the vegetation ash enhanced bacterial growth, while the high Cu, As, and Cr content of the structural ash suppressed growth. Additionally, the overall pattern of upregulated genes and pathways suggests increased virulence potential due to the selection of metal- and antibiotic-resistant strains. Therefore, mixed fire ashes transported and deposited into coastal zones may lead to the selection of environmental reservoirs of Vibrio strains with enhanced antibiotic resistance profiles, increasing public health risk.

Waste Combustion Releases Anthropogenic Nanomaterials in Indigenous Arctic Communities.

Arctic autochthonous communities and the environment face unprecedented challenges due to climate change and anthropogenic activities. One less-explored aspect of these challenges is the release and distribution of anthropogenic nanomaterials in autochthonous communities. This study pioneers a comprehensive investigation into the nature and dispersion of anthropogenic nanomaterials within Arctic Autochthonous communities, originating from their traditional waste-burning practices. Employing advanced nanoanalytical tools, we unraveled the nature and prevalence of nanomaterials, including metal oxides (TiO2, PbO), alloys (SnPb, SbPb, SnAg, SnCu, SnZn), chromated copper arsenate-related nanomaterials (CuCrO2, CuCr2O4), and nanoplastics (polystyrene and polypropylene) in snow and sediment near waste burning sites. This groundbreaking study illuminates the unintended consequences of waste burning in remote Arctic areas, stressing the urgent need for interdisciplinary research, community engagement, and sustainable waste management. These measures are crucial to safeguard the fragile Arctic ecosystem and the health of autochthonous communities.

Physicochemical Characterization of the Particulate Matter in New Jersey/New York City Area, Resulting from the Canadian Quebec Wildfires in June 2023.

The global increase in wildfires, primarily driven by climate change, significantly affects air quality and health. Wildfire-emitted particulate matter (WFPM) is linked to adverse health effects, yet the toxicological mechanisms are not fully understood given its physicochemical complexity and the lack of spatiotemporal exposure data. This study focuses on the physicochemical characterization of WFPM from a Canadian wildfire in June 2023, which affected over 100 million people in the US Northeast, particularly around New Jersey/New York. Aerosol systems were deployed to characterize WFPM during the 3 day event, revealing unprecedented mass concentrations mainly in the WFPM0.1 and WFPM0.1-2.5 size fractions. Peak WFPM2.5 concentrations reached 317 µg/m3, nearly 10 times the National Ambient Air Quality Standard (NAAQS) 24 h average limit. Chemical analysis showed a high organic-to-total carbon ratio (96%), consistent with brown carbon wildfires nanoparticles. Large concentrations of high-molecular-weight PAHs were found predominantly bound to WFPM0.1, with retene, a molecular marker of biomass burning and a known teratogen, being the most abundant (>70%). Computational modeling estimated a total lung deposition of 9.15 mg over 72 h, highlighting the health risks of WFPM, particularly due to its long-distance travel capability and impact on densely populated areas.

Applications of Catalytic Nanomaterials in Energy and Environment.

Nanotechnology is a crucial technology for the development of science and technology [...].

Effect of Nanoparticle Size and Natural Organic Matter Composition on the Bioavailability of Polyvinylpyrrolidone-Coated Platinum Nanoparticles to a Model Freshwater Invertebrate.

The bioavailability of dissolved Pt(IV) and polyvinylpyrrolidone-coated platinum nanoparticles (PtNPs) of five different nominal hydrodynamic diameters (20, 30, 50, 75, and 95 nm) was characterized in laboratory experiments using the model freshwater snail Lymnaea stagnalis. Dissolved Pt(IV) and all nanoparticle sizes were bioavailable to L. stagnalis. Platinum bioavailability, inferred from conditional uptake rate constants, was greater for nanoparticulate than dissolved forms and increased with increasing nanoparticle hydrodynamic diameter. The effect of natural organic matter (NOM) composition on PtNP bioavailability was evaluated using six NOM samples at two nanoparticle sizes (20 and 95 nm). NOM suppressed the bioavailability of 95 nm PtNPs in all cases, and DOM reduced sulfur content exhibited a positive correlation with 95 nm PtNP bioavailability. The bioavailability of 20 nm PtNPs was only suppressed by NOM with a low reduced sulfur content. The physiological elimination of Pt accumulated after dissolved Pt(IV) exposure was slow and constant. In contrast, the elimination of Pt accumulated after PtNP exposures exhibited a triphasic pattern likely involving in vivo PtNP dissolution. This work highlights the importance of PtNP size and interfacial interactions with NOM on Pt bioavailability and suggests that in vivo PtNP transformations could yield unexpectedly higher adverse effects to organisms than dissolved exposure alone.

Metal-Containing Nanoparticles in Low-Rank Coal-Derived Fly Ash from China: Characterization and Implications toward Human Lung Toxicity.

Characterization of nanoparticles (NPs) in coal fly ashes (CFAs) is critical for better understanding the potential health-related risks resulting from coal combustion. Based on single-particle (SP)-inductively coupled plasma mass spectrometry (ICP-MS) coupled with transmission electron microscopy techniques, this study is the first to determine the concentrations and sizes of metal-containing NPs in low-rank coal-derived fly ashes. Despite only comprising a minor component of the studied CFAs by mass, NPs were the dominant fraction by particle number. Fe- and Ti-containing NPs were identified as the dominant NPs with their particle number concentration ranging from 2.5 × 107 to 2.5 × 108 particles/mg. In addition, the differences of Fe-/Ti-containing NPs in various CFAs were regulated by the coalification degree of feed coals and combustion conditions of all of the low-rank CFAs tested. In the cases where these NPs in CFAs become airborne and are inhaled, they can be taken up in pulmonary interstitial fluids. This study shows that in Gamble's solution (a lung fluid simulant), 51-87% of Fe and 63-89% of Ti (ratio of the mass of Fe-/Ti-containing NPs to the total mass of Fe/Ti) exist in the NP form and remain suspended in pulmonary fluid simulants. These NPs are bioavailable and may induce lung tissue damage.

Transport of N-CD and Pre-Sorbed Pb in Saturated Porous Media.

Carbon dots (CDs) are a new type of nanomaterials of the carbon family with unique characteristics, such as their small size (e.g., <10 nm), high water solubility, low toxicity, and high metal affinity. Modification of CDs by Nitrogen functional groups (N-CDs) enhances their metal adsorption capacity. This study investigated the influences of pH (4, 6, and 9), ionic strength (1, 50, and 100 mM), and cation valency (Na+ and Ca2+) on the competitive adsorption of Pb to quartz and N-CD surfaces, the transport and retention of N-CDs in saturated porous media, and the capacity of N-CDs to mobilize pre-adsorbed Pb in quartz columns. Pb adsorption was higher on N-CDs than on quartz surfaces and decreased with increases in ionic strength (IS) and divalent cations (Ca2+) concentration. N-CD mobility in quartz columns was highest at pH of 9- and 1-mM monovalent cations (Na+) and decreased with decreases in pH and increases in ionic strength and ion valency. N-CDs mobilized pre-adsorbed Pb from quartz due to the higher adsorption affinity of Pb to N-CD than to quartz surfaces. These findings provide valuable insights into the transport, retention, and risk assessment of lead in the presence of carbon-based engineered nanoparticles.

Enrichments of Metals, Including Methylmercury, in Sewage Spills in South Carolina, USA.

Exposure to microbial pathogens is the primary concern of sanitary sewer overflows; however, sewage spills may also be a significant source of toxic metals, including methylmercury (MeHg). Between November 2015 and January 2017, after Hurricane Joaquin, surface water samples were collected routinely from three creeks in Columbia, SC. Routine sampling coincided with six sewage spills. Total mercury (THg) and MeHg (unfiltered and filtered) and 32 other metals (filtered) were measured. Compared with surface water samples, THg (unfiltered and filtered), MeHg (unfiltered), and 19 other metals were significantly higher in sewage spills (all log-transformed) (two-tailed test, < 0.05 for all, = 38-42). Toxic weighting factors were applied to 18 metals, including THg and MeHg, in samples collected directly from sewage spills ( = 3-4) and a wastewater outfall ( = 5). On average, sewage was 18.2 and 12.0 times more toxic for THg and MeHg, respectively, and 1.75 times more toxic for all 18 metals, compared to treated effluent from the wastewater outfall. Results suggest sewage spills were a source of inorganic Hg, MeHg, and other metals to the receiving waters and may potentially contribute to water quality impairments.

Citrate-Coated Silver Nanoparticles Growth-Independently Inhibit Aflatoxin Synthesis in Aspergillus parasiticus.

Manufactured silver nanoparticles (Ag NPs) have long been used as antimicrobials. However, little is known about how these NPs affect fungal cell functions. While multiple previous studies reveal that Ag NPs inhibit secondary metabolite syntheses in several mycotoxin producing filamentous fungi, these effects are associated with growth repression and hence need sublethal to lethal NP doses, which besides stopping fungal growth, can potentially accumulate in the environment. Here we demonstrate that citrate-coated Ag NPs of size 20 nm, when applied at a selected nonlethal dose, can result in a >2 fold inhibition of biosynthesis of the carcinogenic mycotoxin and secondary metabolite, aflatoxin B1 in the filamentous fungus and an important plant pathogen, Aspergillus parasiticus, without inhibiting fungal growth. We also show that the observed inhibition was not due to Ag ions, but was specifically associated with the mycelial uptake of Ag NPs. The NP exposure resulted in a significant decrease in transcript levels of five aflatoxin genes and at least two key global regulators of secondary metabolism, laeA and veA, with a concomitant reduction of total reactive oxygen species (ROS). Finally, the depletion of Ag NPs in the growth medium allowed the fungus to regain completely its ability of aflatoxin biosynthesis. Our results therefore demonstrate the feasibility of Ag NPs to inhibit fungal secondary metabolism at nonlethal concentrations, hence providing a novel starting point for discovery of custom designed engineered nanoparticles that can efficiently prevent mycotoxins with minimal risk to health and environment.

Stability and Aggregation Kinetics of Titania Nanomaterials under Environmentally Realistic Conditions.

Nanoparticle morphology is expected to play a significant role in the stability, aggregation behavior, and ultimate fate of engineered nanomaterials in natural aquatic environments. The aggregation kinetics of ellipsoidal and spherical titanium dioxide (TiO2) nanoparticles (NPs) under different surfactant loadings, pH values, and ionic strengths were investigated in this study. The stability results revealed that alteration of surface charge was the stability determining factor. Among five different surfactants investigated, sodium citrate and Suwannee river fulvic acid (SRFA) were the most effective stabilizers. It was observed that both types of NPs were more stable in monovalent salts (NaCl and NaNO3) as compared with divalent salts (Ca(NO3)2 and CaCl2). The aggregation of spherical TiO2 NPs demonstrated a strong dependency on the ionic strength regardless of the presence of mono or divalent salts; while the ellipsoids exhibited a lower dependency on the ionic strength but was more stable. This work acts as a benchmark study toward understanding the ultimate fate of stabilized NPs in natural environments that are rich in Ca(CO3)2, NaNO3, NaCl, and CaCl2 along with natural organic matters.

Association of Arsenic and Phosphorus with Iron Nanoparticles between Streams and Aquifers: Implications for Arsenic Mobility.

The microbial oxidation of organic matter coupled to reductive iron oxide dissolution is widely recognized as the dominant mechanism driving elevated arsenic (As) concentrations in aquifers. This paper considers the potential of nanoparticles to increase the mobility of As in aquifers, thereby accounting for discrepancies between predicted and observed As transport reported elsewhere. Arsenic, phosphorus, and iron size distributions and natural organic matter association were examined along a flow path from surface water via the hyporheic zone to shallow groundwater. Our analysis demonstrates that the colloidal Fe concentration (>1 kDa) correlates with both colloidal P and colloidal As concentrations. Importantly, increases in the concentration of colloidal P (>1 kDa) were positively correlated with increases in the concentration of nominally dissolved As (<1 kDa), but no correlation was observed between colloidal As and nominally dissolved P. This suggests that P actively competes for adsorption sites on Fe nanoparticles, displacing adsorbed As, thus mirroring their interaction with Fe oxides in the aquifer matrix. Dynamic redox fronts at the interface between streams and aquifers may therefore provide globally widespread conditions for the generation of Fe nanoparticles, a mobile phase for As adsorption currently not a part of reactive transport models.

Modeling nanomaterial environmental fate in aquatic systems.

Mathematical models improve our fundamental understanding of the environmental behavior, fate, and transport of engineered nanomaterials (NMs, chemical substances or materials roughly 1-100 nm in size) and facilitate risk assessment and management activities. Although today's large-scale environmental fate models for NMs are a considerable improvement over early efforts, a gap still remains between the experimental research performed to date on the environmental fate of NMs and its incorporation into models. This article provides an introduction to the current state of the science in modeling the fate and behavior of NMs in aquatic environments. We address the strengths and weaknesses of existing fate models, identify the challenges facing researchers in developing and validating these models, and offer a perspective on how these challenges can be addressed through the combined efforts of modelers and experimentalists.

Origin, distribution, fate, and risks of potentially toxic elements in the aquatic environment of Bengaluru metropolis, India.

This study probes the water quality, including pH, total dissolved solids (TDS), and potentially toxic elements (PTEs) concentrations, and the associated environmental and human health implications, in forty one surface water bodies in Bengaluru metropolis, southern India. The pH in 54 %, TDS in 63 %, Ni in 12 %, and U, Mo, Pb, Cr, Co, and Cu in 5 % of the forty one water bodies exceed the WHO's permissible limits for drinking purpose. Total dissolved solids display a significant positive correlation with Pb, Cr, Co, Cu, and Ni, suggesting the association of these elements with particulate matter. Sources of metal pollution include industries in the city's west (high levels of Pb, Cr, Co, Ni, and Cu), traffic in the city Centre (Mo), and geogenic (U) sources in the city's north, east, and south. The degree of contamination is high in 25 %, moderate in 10 %, and low in 65 % of the forty one water bodies, with the highest degree of contamination in Narasappanehalli Lake in the industrial zone, Deepanjali Nagara Lake, and Govindraj Nagar drainage systems. Uranium, Pb, and Mo display a low to medium degree of contamination, whereas Cr, Co, Ni, and Cu display a medium to high degree of contamination. The non-carcinogenic risk through ingestion of contaminated water is medium to high for adults and children and the carcinogenic risk is high in all water bodies. Channels transport contaminated water from Bengaluru water bodies to the Pinakani and Cauvery Rivers and then to the northern Indian Ocean. The states of Karnataka and Tamil Nadu rely on water from these rivers for domestic and agricultural use exposing large populations to contaminated waters. Additionally, contaminated waters can negatively impact flora and fauna of Peninsular India as well as the marine biota of the northern Indian Ocean.

Environmentally persistent free radicals and other paramagnetic species in wildland-urban interface fire ashes.

Wildland-urban interface (WUI) fires consume fuels, such as vegetation and structural materials, leaving behind ash composed primarily of pyrogenic carbon and metal oxides. However, there is currently limited understanding of the role of WUI fire ash from different sources as a source of paramagnetic species such as environmentally persistent free radicals (EPFRs) and transition metals in the environment. Electron paramagnetic resonance (EPR) was used to detect and quantify paramagnetic species, including organic persistent free radicals and transition metal spins, in fifty-three fire ash and soil samples collected following the North Complex Fire and the Sonoma-Lake-Napa Unit (LNU) Lightning Complex Fire, California, 2020. High concentrations of organic EPFRs (e.g., 1.4 × 1014 to 1.9 × 1017 spins g-1) were detected in the studied WUI fire ash along with other paramagnetic species such as iron and manganese oxides, as well as Fe3+ and Mn2+ ions. The mean concentrations of EPFRs in various ash types decreased following the order: vegetation ash (1.1 × 1017 ± 1.1 × 1017 spins g-1) > structural ash (1.6 × 1016 ± 3.7 × 1016 spins g-1) > vehicle ash (6.4 × 1015 ± 8.6 × 1015 spins g-1) > soil (3.2 × 1015 ± 3.7 × 1015 spins g-1). The mean concentrations of EPFRs decreased with increased combustion completeness indicated by ash color; black (1.1 × 1017 ± 1.1 × 1017 spins g-1) > white (2.5 × 1016 ± 4.4 × 1016 spins g-1) > gray (1.8 × 1016 ± 2.4 × 1016 spins g-1). In contrast, the relative amounts of reduced Mn2+ ions increased with increased combustion completeness. Thus, WUI fire ash is an important global source of EPFRs and reduced metal species (e.g., Mn2+). Further research is needed to underpin the formation, transformation, and environmental and human health impacts of these paramagnetic species in light of the projected increased frequency, size, and severity of WUI fires.

Mechanical and self-healing properties of cement paste containing incinerated sugarcane filter cake and Lysinibacillus sp. WH bacteria.

Cement is the most widely used construction material due to its strength and affordability, but its production is energy intensive. Thus, the need to replace cement with widely available waste material such as incinerated black filter cake (IBFC) in order to reduce energy consumption and the associated CO2 emissions. However, because IBFC is a newly discovered cement replacement material, several parameters affecting the mechanical properties of IBFC-cement composite have not been thoroughly investigated yet. Thus, this work aims to investigate the impact of IBFC as a cement replacement and the addition of the calcifying bacterium Lysinibacillus sp. WH on the mechanical and self-healing properties of IBFC cement pastes. The properties of the IBFC-cement pastes were assessed by determining compressive strength, permeable void, water absorption, cement hydration product, and self-healing property. Increases in IBFC replacement reduced the durability of the cement pastes. The addition of the strain WH to IBFC cement pastes, resulting in biocement, increased the strength of the IBFC-cement composite. A 20% IBFC cement-replacement was determined to be the ideal ratio for producing biocement in this study, with a lower void percentage and water absorption value. Adding strain WH decreases pore sizes, densifies the matrix in ≤ 20% IBFC biocement, and enhances the formation of calcium silicate hydrate (C-S-H) and AFm ettringite phases. Biogenic CaCO3 and C-S-H significantly increase IBFC composite strength, especially at ≤ 20% IBFC replacement. Moreover, IBFC-cement composites with strain WH exhibit self-healing properties, with bacteria precipitating CaCO3 crystals to bridge cracks within two weeks. Overall, this work provides an approach to produce a "green/sustainable" cement using biologically enabled self-healing characteristics.

Unveiling elemental fingerprints: A comparative study of clustering methods for multi-element nanoparticle data.

Single particle-inductively coupled plasma-time of flight-mass spectrometers (SP-ICP-TOF-MS) generates large datasets of the multi-elemental composition of nanoparticles. However, extracting useful information from such datasets is challenging. Hierarchical clustering (HC) has been successfully applied to extract elemental fingerprints from multi-element nanoparticle data obtained by SP-ICP-TOF-MS. However, many other clustering approaches can be applied to analyze SP-ICP-TOF-MS data that have not yet been evaluated. This study fills this knowledge gap by comparing the performance of three clustering approaches: HC, spectral clustering, and t-distributed Stochastic Neighbor Embedding coupled with Density-Based Spatial Clustering of Applications with Noise (tSNE-DBSCAN) for analyzing SP-ICP-TOF-MS data. The performance of these clustering techniques was evaluated by comparing the size of the extracted clusters and the similarity of the elemental composition of nanoparticles within each cluster. Hierarchical clustering often failed to achieve an optimal clustering solution for SP-ICP-TOF-MS data because HC is sensitive to the presence of outliers. Spectral clustering and tSNE-DBSCAN extracted clusters that were not identified by HC. This is because spectral clustering, a method developed based on graph theory, reveals the global and local structure in the data. tSNE reduces and maps the data into a lower-dimensional space, enabling clustering algorithms such as DBSCAN to identify subclusters with subtle differences in their elemental composition. However, tSNE-DBSCAN can lead to unsatisfactory clustering solutions because tuning the perplexity hyperparameter of tSNE is a difficult and a time-consuming task, and the relative distance between datapoints is not maintained. Although the three clustering approaches successfully extract useful information from SP-ICP-TOF-MS data, spectral clustering outperforms HC and tSNE-DBSCAN by generating clusters of a large number of nanoparticles with similar elemental compositions.

Identification and quantification of Cr, Cu, and As incidental nanomaterials derived from CCA-treated wood in wildland-urban interface fire ashes.

In addition to the combustion of vegetation, fires at the wildland-urban interface (WUI) burn structural materials, including chromated copper arsenate (CCA)-treated wood. This study identifies, quantifies, and characterizes Cr-, Cu-, and As-bearing incidental nanomaterials (INMs) in WUI fire ashes collected from three residential structures suspected to have originated from the combustion of CCA-treated wood. The total elemental concentrations were determined by inductively coupled plasma-time of flight-mass spectrometry (ICP-TOF-MS) following acid digestion. The crystalline phases were determined using transmission electron microscopy (TEM), specifically using electron diffraction and high-resolution imaging. The multi-element single particle composition and size distribution were determined by single particle (SP)-ICP-TOF-MS coupled with agglomerative hierarchical clustering analysis. Chromium, Cu, and As are the dominant elements in the ashes and together account for 93%, 83%, and 24% of the total mass of measured elements in the ash samples. Chromium, Cu, and As phases, analyzed by TEM, most closely match CrO3, CrO2, eskolaite (Cr2O3), CuCrO2, CuCr2O4, CrAs2O6, As2O5, AsO2, claudetite (As2O3, monoclinic), or arsenolite (As2O3, cubic), although a bona fide phase identification for each particle was not always possible. These phases occur predominantly as heteroaggregates. Multi-element single particle analyses demonstrate that Cr occurs as a pure phase (i.e., Cr oxides) as well as in association with other elements (e.g., Cu and As); Cu occurs predominantly in association with Cr and As; and As occurs as As oxides and in association with Cu and Cr. Several Cr, Cu, and As clusters were identified and the molar ratios of Cr/Cu and Cr/As within these clusters are consistent with the crystalline phases identified by TEM as well as their heteroaggregates. These results indicate that WUI fires can lead to significant release of CCA constituents and their combustion-transformed by-products into the surrounding environment. This study also provides a method to identify and track CCA constituents in environmental systems based on multi-element analysis using SP-ICP-TOF-MS.

Wildland-urban interface fire ashes as a major source of incidental nanomaterials.

Although metal and metalloid concentrations in wildfire ashes have been documented, the nature and concentrations of incidental nanomaterials (INMs) in wildland-urban interface (WUI) fire ashes have received considerably less attention. In this study, the total metal and metalloid concentrations of 57 vegetation, structural, and vehicle ashes and underlying soils collected at the WUI following the 2020 fire season in northern California - North Complex Fire and LNU Lightning Complex Fire - were determined using inductively coupled plasma-time of flight-mass spectrometry after microwave-assisted acid digestion. The concentrations of Ti, Zn, Cu, Ni, Pb, Sn, Sb, Co, Bi, Cr, Ba, As, Rb, and W are generally higher in structural/vehicle-derived ashes than in vegetation-derived ashes and soils. The concentrations of Ca, Sr, Rb, and Ag increased with increased combustion completeness (e.g., black ash < gray ash < white ash), whereas those of C, N, Zn, Pb, and In decreased with increased combustion completeness. The concentration of anthropogenic Ti - determined by mass balance calculations and shifts in Ti/Nb above the natural background ratios - was highest in vehicle ash (median: 30.8 g kg-1, range: 4.5-41.0 g kg-1) followed by structural ash (median: 5.5 g kg-1, range: of 0-77.4 g kg-1). Various types of carbonaceous INM (e.g., amorphous carbon, turbostratic-like carbon, and carbon associated with zinc oxides) and metal-bearing INMs (e.g., Ti, Cu, Fe, Zn, Mn, Pb, and Cr) with sizes between few nanometers to few hundreds of nanometers were evidenced in ashes using transmission electron microscopy, including energy dispersive X-ray spectroscopy. Overall, this study demonstrates the abundance of a variety of metals and metalloids in the form of INMs in WUI fire ashes. This study also highlights the need for further research into the formation, transformation, reactivity, fate, and effects of INMs during and following fires at the WUI.

The elemental fingerprint as a potential tool for tracking the fate of real-life model nanoplastics generated from plastic consumer products in environmental systems.

Metals and metalloids are widely used in producing plastic materials as fillers and pigments, which can be used to track the environmental fate of real-life nanoplastics in environmental and biological systems. Therefore, this study investigated the metal and metalloids concentrations and fingerprint in real-life model nanoplastics generated from new plastic products (NPP) and from environmentally aged ocean plastic fragments (NPO) using single particle-inductively coupled plasma-mass spectrometry (SP-ICP-TOF-MS) and transmission electron microscopy coupled with energy dispersive X-ray spectroscopy (TEM-EDX). The new plastic products include polypropylene straws (PPS), polyethylene terephthalate bottles (PETEB), white low-density polyethylene bags (LDPEB), and polystyrene foam shipping material (PSF). All real-life model nanoplastics contained metal and metalloids, including Si, Al, Sr, Ti, Fe, Ba, Cu, Pb, Zn, Cd, and Cr, and were depleted in rare earth elements. Nanoplastics generated from the white LDPEB were rich in Ti-bearing particles, whereas those generated from PSF were rich in Cr, Ti, and Pb. The Ti/Fe in the LDPEB nanoplastics and the Cr/Fe in the PSF nanoplastics were higher than the corresponding ratios in natural soil nanoparticles (NNPs). The Si/Al ratio in the PSF nanoplastics was higher than in the NNPs, possibly due to silica-based fillers. The elemental ratio of Si/Al, Fe/Cr, and Fe/Ni in the nanoplastics derived from ocean plastic fragments was intermediate between the nanoplastics derived from real-life plastic products and NNPs, indicating a combined contribution from pigments and fillers used in plastics and from natural sources. This study provides a method to track real-life nanoplastics in controlled laboratory studies based on nanoplastic elemental fingerprints. It expands the realm of nanoplastics that can be followed based on their metallic signatures to all kinds of nanoplastics. Additionally, this study illustrates the importance of nanoplastics as a source of metals and metal-containing nanoparticles in the environment.

Results of an interlaboratory comparison for characterization of Pt nanoparticles using single-particle ICP-TOFMS.

This study describes an interlaboratory comparison (ILC) among nine (9) laboratories to evaluate and validate the standard operation procedure (SOP) for single-particle (sp) ICP-TOFMS developed within the context of the Horizon 2020 project ACEnano. The ILC was based on the characterization of two different Pt nanoparticle (NP) suspensions in terms of particle mass, particle number concentration, and isotopic composition. The two Pt NP suspensions were measured using icpTOF instruments (TOFWERK AG, Switzerland). Two Pt NP samples were characterized and mass equivalent spherical sizes (MESSs) of 40.4 ± 7 nm and 58.8 ± 8 nm were obtained, respectively. MESSs showed <16% relative standard deviation (RSD) among all participating labs and <4% RSD after exclusion of the two outliers. A good agreement was achieved between the different participating laboratories regarding particle mass, but the particle number concentration results were more scattered, with <53% RSD among all laboratories, which is consistent with results from previous ILC studies conducted using ICP-MS instrumentation equipped with a sequential mass spectrometer. Additionally, the capabilities of sp-ICP-TOFMS to determine masses on a particle basis are discussed with respect to the potential for particle density determination. Finally, because quasi-simultaneous multi-isotope and multi-element determinations are a strength of ICP-TOFMS instrumentation, the precision and trueness of isotope ratio determinations were assessed. The average of 1000 measured particles yielded a precision of below ±1% for intensity ratios of the most abundant Pt isotopes, i.e.194Pt and 195Pt, while the accuracy of isotope ratios with the lower abundant isotopes was limited by counting statistics.