Species selective concentration and determination of nano-selenium and inorganic selenium species in environmental waters by micropore membrane filtration and ICP-MS.

Accurate quantification of nano-selenium (nSe) and other ionic Se species in aquatic environments is a prerequisite for reliable estimation of their potential hazards. In this study, a micropore membrane filtration-based method followed by ICP-MS analysis was proposed for the selective concentration and determination of nSe in the water column. Polyvinylidene fluoride (PVDF) and nylon micropore filtration membranes were proven to efficiently capture nSe under optimal conditions (retention > 91.0 ± 0.87%). At the same time, ionic selenite and selenate could escape from the membranes, realizing the isolation of nSe and ionic Se species. The interference of dissolved organic matter (DOM) during separation can be resolved by adding Ca(II) ions, which can induce the formation of DOM aggregates by cation bridging effects. nSe retained on PVDF membranes could be effectively eluted with FL-70 (a powerful alkaline surfactant) aqueous solutions (0.5%, m/v) while maintaining the original size and morphology. Although nSe trapped on nylon membranes could not be easily eluted, quantification can also be achieved after membrane digestion. Speciation of ionic selenite and selenate in the filtrate was further conducted with an anion exchange column by using HPLC coupled with ICP-MS. The developed method was used to analyze Se species in six real water samples. Spiking experiments showed that the recoveries of nSe ranged from 70.2 ± 2.7% to 85.8 ± 1.3% at a spike level of 0.2 µg/L, and the recoveries of Se(IV) and Se(VI) ranged from 83.6 ± 0.5% to 101 ± 1% at a spike level of 0.55 µg/L, verifying the feasibility for the analysis of environmental water samples. This work provides possibilities to investigate the transformation and potential risks of nSe in the environment.

In situ characterization of silver nanoparticles sulfidation processes in aquatic solution by hollow fiber flow-field flow fractionation coupled with ICP-QQQ.

The sulfidation is considered as one of the most important environmental transformation processes of silver nanoparticles (AgNPs), which affects their transport, uptake and toxicity. Herein, based on the hollow fiber flow-field flow fractionation coupled with triple quadrupole inductively coupled plasma mass spectrometry (HF5-ICP-QQQ), we developed an efficient approach to accurately characterize the sulfidation process of AgNPs in aquatic solutions. HF5 could efficiently remove interferential ions and separate nanoparticles with different sizes online, and ICP-QQQ could accurately detect S element through monitoring 32S16O+ in mass shift mode. By the proposed method, two kinds of AgNPs, citrate-coated AgNPs and PVP-coated AgNPs, were selected as models to trace their transfer behaviors during the sulfidation. The results showed once AgNPs were exposed to Na2S solution, the overlapping fractograms of 32S16O+ and 107Ag+ were rapidly detected by HF5-ICP-QQQ to indicate the co-presence of Ag and S, and thus confirming the production of Ag2S and AgNPs underwent a rapid sulfidation process. There were substantial differences in the influence of the two coated agents on the stability of the particles under the conditions examined. In the presence of sulfide, PVP-coated AgNPs could maintain initial size distribution with higher stability, while the size distribution of citrate-coated AgNPs changed considerably. The developed HF5-ICP-QQQ method provides a reliable tool to identify and characterize the transformation process of AgNPs in aquatic solution, which contributed to a deeper understanding of the environmental fate and behavior of AgNPs with different coating.

Spatiotemporal dynamics of dissolved organic matter and disinfection by-products formation potential of Shengzhong Lake in southwest China.

The quality and quantity of dissolved organic matter (DOM) in lakes as well as its environmental effects associated with the unintended disinfection by-products (DBPs) have received continuous attention. This work investigated the spatiotemporal dynamics of DOM in Shengzhong Lake in southwest China and the formed DBPs during the chlorine disinfection process. The results showed that lake water in summer had significantly higher dissolved oxygen and dissolved organic carbon than that in winter. In contrast, DOM in winter demonstrated an obviously higher aromaticity and molecular weight than that in summer. Four fluorescence components, i.e., terrestrial humic-like substances (C1), protein-like substances (C2), and microbial humic-like substances (C3 and C4), were identified, and their relative abundance followed in the order of C3 > C4 > C2 > C1 in winter and C4 > C3 > C1 > C2 in summer. The formation potential of trihalomethanes and haloacetic acids in winter was higher and lower than that in summer, which was mainly ascribed to the content of aromatic and hydrophobic substances. Compared to the significant seasonal dynamic, the spatial variation of DOM and the formed DBPs was not obvious. This work sheds light on the spatial-temporal distribution of DOM and the potentially formed DBPs in Shengzhong Lake, and will be helpful for understanding the biogeochemical cycle of carbon and assessing the drinking water safety.

Micro(nano)plastics in the Human Body: Sources, Occurrences, Fates, and Health Risks.

The increasing global attention on micro(nano)plastics (MNPs) is a result of their ubiquity in the water, air, soil, and biosphere, exposing humans to MNPs on a daily basis and threatening human health. However, crucial data on MNPs in the human body, including the sources, occurrences, behaviors, and health risks, are limited, which greatly impedes any systematic assessment of their impact on the human body. To further understand the effects of MNPs on the human body, we must identify existing knowledge gaps that need to be immediately addressed and provide potential solutions to these issues. Herein, we examined the current literature on the sources, occurrences, and behaviors of MNPs in the human body as well as their potential health risks. Furthermore, we identified key knowledge gaps that must be resolved to comprehensively assess the effects of MNPs on human health. Additionally, we addressed that the complexity of MNPs and the lack of efficient analytical methods are the main barriers impeding current investigations on MNPs in the human body, necessitating the development of a standard and unified analytical method. Finally, we highlighted the need for interdisciplinary studies from environmental, biological, medical, chemical, computer, and material scientists to fill these knowledge gaps and drive further research. Considering the inevitability and daily occurrence of human exposure to MNPs, more studies are urgently required to enhance our understanding of their potential negative effects on human health.

Critical Review of Pd-Catalyzed Reduction Process for Treatment of Waterborne Pollutants.

Catalyzed reduction processes have been recognized as important and supplementary technologies for water treatment, with the specific aims of resource recovery, enhancement of bio/chemical-treatability of persistent organic pollutants, and safe handling of oxygenate ions. Palladium (Pd) has been widely used as a catalyst/electrocatalyst in these reduction processes. However, due to the limited reserves and high cost of Pd, it is essential to gain a better understanding of the Pd-catalyzed decontamination process to design affordable and sustainable Pd catalysts. This review provides a systematic summary of recent advances in understanding Pd-catalyzed reductive decontamination processes and designing Pd-based nanocatalysts for the reductive treatment of water-borne pollutants, with special focus on the interactions and transformation mechanisms of pollutant molecules on Pd catalysts at the atomic scale. The discussion begins by examining the adsorption of pollutants onto Pd sites from a thermodynamic viewpoint. This is followed by an explanation of the molecular-level reaction mechanism, demonstrating how electron-donors participate in the reductive transformation of pollutants. Next, the influence of the Pd reactive site structure on catalytic performance is explored. Additionally, the process of Pd-catalyzed reduction in facilitating the oxidation of pollutants is briefly discussed. The longevity of Pd catalysts, a crucial factor in determining their practicality, is also examined. Finally, we argue for increased attention to mechanism study, as well as precise construction of Pd sites under batch synthesis conditions, and the use of Pd-based catalysts/electrocatalysts in the treatment of concentrated pollutants to facilitate resource recovery.

Deciphering Vanadium Speciation in Smelting Ash and Adaptive Responses of Soil Microorganisms.

Abundant smelting ash is discharged during pyrometallurgical vanadium (V) production. However, its associated V speciation and resultant ecological impact have remained elusive. In this study, V speciation in smelting ash and its influence on the metabolism of soil microorganisms were investigated. Smelting ashes from V smelters contained abundant V (19.6-115.9 mg/g). V(V) was the dominant species for soluble V, while solid V primarily existed in bioavailable forms. Previously unrevealed V nanoparticles (V-NPs) were prevalently detected, with a peak concentration of 1.3 × 1013 particles/g, a minimal size of 136.0 ± 0.6 nm, and primary constituents comprising FeVO4, VO2, and V2O5. Incubation experiments implied that smelting ash reshaped the soil microbial community. Metagenomic binning, gene transcription, and component quantification revealed that Microbacterium sp. and Tabrizicola sp. secreted extracellular polymeric substances through epsB and yhxB gene regulation for V-NPs aggregation to alleviate toxicity under aerobic operations. The V K-edge X-ray absorption near-edge structure (XANES) spectra suggested that VO2 NPs were oxidized to V2O5 NPs. In the anaerobic case, Comamonas sp. and Achromobacter sp. reduced V(V) to V(IV) for detoxification regulated by the napA gene. This study provides a deep understanding of the V speciation in smelting ash and microbial responses, inspiring promising bioremediation strategies to reduce its negative environmental impacts.

Superhydrophobic magnetic Fe3O4 polyurethane sponges for oil-water separation and oil-spill recovery.

The effective and affordable separation of oil and water, a crucial process in the safe handling of environmental disasters such as crude oil spills and recovery of valuable resources, is a highly sought-after yet challenging task. Herein, superhydrophobic PU sponge was fabricated for the fast and cost-effective adsorptive separation of oil and different organic solvents from water. Octadecyltrichlorosilane (OTS)-functionalized Fe3O4@SiO2 core-shell microspheres were dip-coated on the surface of porous materials via a dip-coating process, thereby endowing them with superhydrophobicity. Owing to the hydrophobic interaction between OTS molecules and oil and increased capillary force in the micropores, the resulting superhydrophobic sponge served as a selective oil-sorbent scaffold for absorbing oil from oil-water mixtures, including oil-water suspensions and emulsions. Remarkably, after the recovery of the adsorbed oil via mechanical extrusion, these superhydrophobic materials could be reused multiple times and maintain their oil-water separation efficacy even after 10 oil-water separation cycles.

Speciation of Selenium Nanoparticles and Other Selenium Species in Soil: Simple Extraction Followed by Membrane Separation and ICP-MS Determination.

The application of selenium nanoparticle (SeNP)-based fertilizers can cause SeNPs to enter the soil environment. Considering the possible transformation of SeNPs and the species-dependent toxicity of selenium (Se), accurate analysis of SeNPs and other Se species present in the soil would help rationally assess the potential hazards of SeNPs to soil organisms. Herein, a novel method for speciation of SeNPs and other Se species in soil was established. Under the optimized conditions, SeNPs, selenite, selenate, and seleno amino acid could be simultaneously extracted from the soil with mixtures of tetrasodium pyrophosphate (5 mM) and potassium dihydrogen phosphate (1.2 µM), while inert Se species (mainly metal selenide) remained in the soil. Then, extracted SeNPs can be effectively captured by a nylon membrane (0.45 µm) and quantified by inductively coupled plasma mass spectrometry (ICP-MS). Other extracted Se species can be separated and quantified by high-performance liquid chromatography coupled with ICP-MS. Based on the difference between the total Se contents and extracted Se contents, the amount of metal selenide can be calculated. The limits of detection of the method were 0.02 µg/g for SeNPs, 0.05 µg/g for selenite, selenate, and selenocystine, and 0.25 µg/g for selenomethionine, respectively. Spiking experiments also showed that our method was applicable to real soil sample analysis. The present method contributes to understanding the speciation of Se in the soil environment and further estimating the occurrence and application risks of SeNPs.

Nanoparticulate pollutants in the environment: Analytical methods, formation, and transformation.

The wide application of nanomaterials and plastic products generates a substantial number of nanoparticulate pollutants in the environment. Nanoparticulate pollutants are quite different from their bulk counterparts because of their unique physicochemical properties, which may pose a threat to environmental organisms and human beings. To accurately predict the environmental risks of nanoparticulate pollutants, great efforts have been devoted to developing reliable methods to define their occurrence and track their fate and transformation in the environment. Herein, we summarized representative studies on the preconcentration, separation, formation, and transformation of nanoparticulate pollutants in environmental samples. Finally, some perspectives on future research directions are proposed.

Direct entry of micro(nano)plastics into human blood circulatory system by intravenous infusion.

Understanding the pathways of human exposure to micro(nano)plastics (MNPs) is crucial for assessing their health impacts. Intravenous infusion can induce MNPs direct entry into the human blood, posing serious risks on human health, but remains unclear. Herein, we developed comprehensive analytical methods to detect polyvinyl chloride (PVC) MNPs down to 20 nm, and found about 0.52 µg equal to 105-1011 particles of PVC-MNPs released from intravenous infusion products (IVIPs) during each intravenous infusion of 250 mL injection. The released amounts of MNPs from IVIPs were dependent on the plastic materials, and the injection volume and composition. These findings indicated that the released MNPs should be directly introduced into the human blood circulatory system, causing serious impacts on human health. Our study reveals a previously ignored but important pathway of human exposure to MNPs, and calls for further research on the potential risks of these MNPs on human health.

Different Expression Profiles of Exosomal circRNAs from Apheresis Platelets during Storage.

Introduction: Bioactive substances of stored platelets change during the stored periods. Exosomes are reported to be increased during platelet storage. Circular RNAs (circRNAs) are one of the main components in exosomes. It is the purpose of this study to investigate the different expression of exosomal circRNAs during storage. Methods: Apheresis platelets were collected from 7 healthy volunteers and stored in platelet storage bags for 1 day or 5 days. We isolated exosomes by ultracentrifugation and characterized exosomes by transmission electron microscopy, nano-flow cytometry, and Western blot. We conducted microarray analysis to detect changes in the exosomal circRNAs from apheresis platelets during storage, and qRT-PCR to validate their expressions. To analyze the competing endogenous RNA (ceRNA) of circRNAs, microRNAs (miRNAs) targets were predicted based on interactions of circRNAs/miRNAs and miRNAs/mRNAs, using TargetScan and miRanda. A ceRNA network was constructed by Cytoscape. The targeted mRNAs were performed for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) pathway analysis by the DAVID. Results: Microarray analysis revealed that 61 differentially expressed circRNAs between day 1 and day 5. Thirty-one circRNAs of these are upregulated, while 30 circRNAs are downregulated. A ceRNA visualized network includes 9 circRNAs, 48 miRNAs, and 117 mRNAs. There were 117 mRNAs enriched in 203 GO terms and 9 KEGG pathways based on the GO and KEGG pathway enrichment analyses. Conclusion: We identified 61 dysregulated exosomal circRNAs from apheresis platelets during storage. The study provided insights into the underlying mechanisms of platelet storage lesion.

Comparison of transfusion rates between robotic- and video-assisted lobectomy: a propensity score matching analysis.

The objective is to compare the perioperative blood transfusion rate and postoperative complications between robot-assisted surgery and thoracoscopic surgery in lung cancer patients. This is a single-center retrospective study. Patients underwent lung cancer minimally invasive resection at Fujian Cancer Hospital from April 1, 2022, to April 30, 2023, were enrolled in this study. Patients were divided into robotic-assisted lobectomy (RAL) and video-assisted lobectomy (VAL) groups according to the surgical methods. Data, including demographics, clinic variables, and endpoint outcomes were collected from the electronic medical record. Propensity score matching (PSM) was performed to analyze the baseline data of patients. The RAL group and the VAL group were matched 1:1. Then, the blood transfusion rates and short-term outcomes of the two groups were compared. A logistic regression was performed to analyze the independent risk factors of perioperative blood transfusion. A total of 558 patients were enrolled in this study. 166 of 558 patients were divided into the RAL group, and 392 patients were into the VAL group. A total of 118 patients were selected and analyzed following propensity score matching. After PSM, there was no difference in perioperative transfusion rates, including RBC transfusion and frozen plasma transfusion, between the VAL and RAL groups (P > 0.05). The RAL group had fewer days of drainage tubes (P = 0.036). There was no difference in other short-term outcomes, including the volume of thoracic drainage, the volume of intraoperative blood loss, the length of hospitalization, and the rate of postoperative pulmonary infection (P > 0.05). Volume of intraoperative blood loss, volume of thoracic drainage, and preoperative hemoglobin were independent risk factors of perioperative red blood cell or frozen plasma transfusion; however, RAL or VAL was not. The study showed that the rates of perioperative blood transfusion were comparable between RAL and VAL. RAL is superior for patient recovery in terms of short-term outcomes.

Extraction of Common Small Microplastics and Nanoplastics Embedded in Environmental Solid Matrices by Tetramethylammonium Hydroxide Digestion and Dichloromethane Dissolution for Py-GC-MS Determination.

Determination of microplastics and nanoplastics (MNPs), especially small MPs and NPs (<150 µm), in solid environmental matrices is a challenging task due to the formation of stable aggregates between MNPs and natural colloids. Herein, a novel method for extracting small MPs and NPs embedded in soils/sediments/sludges has been developed by combining tetramethylammonium hydroxide (TMAH) digestion with dichloromethane (DCM) dissolution. The solid samples were digested with TMAH, and the collected precipitate was washed with anhydrous ethanol to eliminate the natural organic matter. Then, the MNPs in precipitate were extracted by dissolving in DCM under ultrasonic conditions. Under the optimized digestion and extraction conditions, the factors including sizes and concentrations of MNPs showed insignificant effects on the extraction process. The feasibility of this sample preparation method was verified by the satisfactory spiked recoveries (79.6-91.4%) of polystyrene, polyethylene, polypropylene, poly(methyl methacrylate), polyvinyl chloride, and polyethylene terephthalate MNPs in soil/sediment/sludge samples. The proposed sample preparation method was coupled with pyrolysis gas chromatography-mass spectrometry to determine trace small MPs and NPs with a relatively low detection limit of 2.3-29.2 µg/g. Notably, commonly used MNPs were successfully detected at levels of 4.6-51.4 µg/g in 6 soil/sediment/sludge samples. This proposed method is promising for evaluating small solid-embedded MNP pollution.

Opportunities for the use of selenium nanoparticles in agriculture.

Due to the growing number of the world's population, there is an urgent need for high-quality food to meet global food security. Traditional fertilizers and pesticides face the problems of low utilization efficiency and possible hazards to non-target organisms. Selenium (Se) is an essential trace element for animals and humans. As a result, Se nanoparticles (SeNPs) have aroused intense interest and found opportunities in agricultural use. Herein, we summarized representative studies on the potential application of SeNPs in agriculture, including mitigating biotic and abiotic stresses in plants, promoting seed germination and plant growth, and improving Se contents and nutritional values in crops, and the underlying mechanisms were also discussed. Finally, future directions are highlighted to get a deep insight into this field.

Quantitation of Atmospheric Suspended Polystyrene Nanoplastics by Active Sampling Prior to Pyrolysis-Gas Chromatography-Mass Spectrometry.

Plastic has been demonstrated to release nanoplastics (NPs) into the atmosphere under sunlight irradiation, posing a continuous health risk to the respiratory system. However, due to lack of reliable quantification methods, the occurrence and distribution of NPs in the atmosphere remain unclear. Polystyrene (PS) micro- and nanoplastics (MNPs) represent a crucial component of atmospheric MNPs. In this study, we proposed a simple and robust method for determining the concentration of atmospheric PS NPs using pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). Following active sampling, the filter membrane is directly ground and introduced into the Py-GC/MS system to quantify PS NPs. The proposed method demonstrates excellent reproducibility and high sensitivity, with a detection limit as low as down to 15 pg/m3 for PS NPs. By using this method, the occurrence of PS NPs in both indoor and outdoor atmospheres has been confirmed. Furthermore, the results showed that the abundance of outdoor PS NPs was significantly higher than that of indoor samples, and there was no significant difference in NP vertical distribution within a height of 28.6 m. This method can be applied for the routine monitoring of atmospheric PS NPs and for evaluating their risk to human health.

Molecular probing of dissolved organic matter and its transformation in a woolen textile wastewater treatment station.

Woolen textile industry produces enormous wastewater (WTIW) with high pollution loads, and needs to be treated by wastewater treatment stations (WWTS) before centralized treatment. However, WTIW effluent still contains many biorefractory and toxic substances; thus, comprehensive understandings of dissolved organic matter (DOM) of WTIW and its transformation are essential. In this study, total quantity indices, size exclusion chromatography, spectral methods, and Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) were used for comprehensively characterizing DOM and its transformation during full-scale treatments, including influent, regulation pool (RP), flotation pool (FP), up-flow anaerobic sludge bed (UA), anaerobic/oxic (AO) and effluent. DOM in influent featured a large molecular weight (5-17 kDa), toxicity (0.201 HgCl2 mg/L), and a protein content of 338 mg C/L. FP largely removed 5-17 kDa DOM with the formation of 0.45-5 kDa DOM. UA and AO removed 698 and 2042 chemicals, respectively, which were primarily saturated components (H/C > 1.5); however, both UA and AO contributed to the formation of 741 and 1378 stable chemicals, respectively. Good correlations were found among water quality indices and spectral/molecular indices. Our study reveals the molecular composition and transformation of WTIW DOM during treatments and encourages the optimization of the employed processes in WWTS.

Efficient immobilization and detoxification of gaseous elemental mercury by nanoflower/rod WSe2/halloysite composite: Performance and mechanisms.

Gaseous mercury pollution control technologies with low stability and high releasing risks always face with great challenges. Herein, we developed one halloysite nanotubes (HNTs)-supported tungsten diselenide (WSe2) composite (WSe2/HNTs) by one-pot solvothermal approach, curing Hg0 from complicated flue gas (CFG) and reducing second environment risks. WSe2 as a monolayer with nano-flower structure and HNTs with rod shapes in the as-prepared sorbent exhibited outstanding synergy efficiency, resulting in exceptional performance for Hg0 removal with high capture capacity of 30.6 mg·g-1 and rate of 9.09 µg·g-1·min-1, which benefited from the high affinity of selenium and mercury (1 ×1045) and the adequate exposure of Se-terminated. The adsorbent showed beneficial tolerance to high amount of NOx and SOx. An online lab-built thermal decomposition system (TPD-AFS) was employed to explore Hg species on the used-sorbent, finding that the adsorbed-mercury species were principally mercury selenide (HgSe). Density functional theory calculations indicated that the hollow-sites were the major adsorption sites and exhibited excellent selectivity for Hg0, as well as HgSe generation needed to overcome the 0.32 eV energy barrier. The adsorbed mercury displayed high environmental stability after the leaching toxicity test, which significantly decreased its secondary environmental risks. With these advantages, WSe2/HNTs possess enormous potential to achieve the effective and permanent immobilization of gaseous mercury from CFG in the future.

Blockage of ATPase-mediated energy supply inducing metabolic disturbances in algal cells under silver nanoparticles stress.

Adenosine triphosphate (ATP) generation of aquatic organisms is often subject to nanoparticles (NPs) stress, involving extensive reprogramming of gene expression and changes in enzyme activity accompanied by metabolic disturbances. However, little is known about the mechanism of energy supply by ATP to regulate the metabolism of aquatic organisms under NPs stress. Here, we selected extensively existing silver nanoparticles (AgNPs) to investigate their implications on ATP generation and relevant metabolic pathways in alga (Chlorella vulgaris). Results showed that ATP content significantly decreased by 94.2% of the control (without AgNPs) in the algal cells at 0.20 mg/L AgNPs, which was mainly attributed to the reduction of chloroplast ATPase activity (81.4%) and the downregulation of ATPase-coding genes atpB and atpH (74.5%-82.8%) in chloroplast. Molecular dynamics simulations demonstrated that AgNPs competed with the binding sites of substrates adenosine diphosphate and inorganic phosphate by forming a stable complex with ATPase subunit beta, potentially resulting in the reduced binding efficiency of substrates. Furthermore, metabolomics analysis proved that the ATP content positively correlated with the content of most differential metabolites such as D-talose, myo-inositol, and L-allothreonine. AgNPs remarkably inhibited ATP-involving metabolic pathways, including inositol phosphate metabolism, phosphatidylinositol signaling system, glycerophospholipid metabolism, aminoacyl-tRNA biosynthesis, and glutathione metabolism. These results could provide a deep understanding of energy supply in regulating metabolic disturbances under NPs stress.

Spatial distribution of polystyrene nanoplastics and small microplastics in the Bohai Sea, China.

Micro- and nano-plastic (MNP) pollution has attracted public concerns. Currently, most environmental researches focus on large microplastics (MPs), while small MNPs that have great impacts on marine ecosystems are rarely reported. Understanding the pollution levels and distribution patterns of small MNPs could help assess their potential impacts on the ecosystem. Polystyrene (PS) MNPs were often used as models to assess their toxicity, hence, we collected 21 sites in a Chinese sea area (the Bohai Sea) to analyze their pollution level and horizontal distribution in surface water samples, and vertical distributions in five sites with the water depth >25 m. Samples were filtered by glass membranes (1 µm) to trap MPs, which were frozen, ground, dried, and detected by pyrolysis-gas chromatography-mass spectrometry (pyGC-MS); while the nanoplastics (NPs) in the filtrate were captured with alkylated ferroferric oxide (Fe3O4) to form aggregates, which were separated by glass membrane (300 nm) filtration for pyGC-MS determination. Small PS MPs (1-100 µm) and NPs (<1 µm) were detected in 18 samples with the mass concentrations ranging from <0.015 to 0.41 µg/L, indicating that PS MNPs are widely present in Bohai Sea. Our study contributes to understanding the pollution levels and distribution patterns of MNPs (<100 µm) in the marine system and provides valuable data for their further risk assessment.

Determination of the Particle Number Concentration, Size Distribution, and Species of Dominant Silver-Containing Nanoparticles in Soils by Single-Particle ICP-MS.

The potential risk of various silver-containing nanoparticles (AgCNPs) in soils is related to the concentration, size, and speciation, but their determination remains a great challenge. Herein, we developed an effective method for determining the particle number, size, and species of dominant AgCNPs in soils, including nanoparticles of silver (Ag NPs), silver chloride (AgCl NPs), and silver sulfide (Ag2S NPs). By ultrasonication wand-assisted tetrasodium pyrophosphate extraction, these AgCNPs were extracted efficiently from soils. Then, multistep selective dissolution of Ag NPs, AgCl NPs, and whole Ag NPs/AgCl NPs/Ag2S NPs was achieved by 1% (v/v) H2O2, 5% (v/v) NH3·H2O, and 10 mM thiourea in 2% (v/v) acetic acid, respectively. Finally, the particle number concentration and size distribution of AgCNPs in the extracts and the remaining AgCNP particle number concentration after each dissolution were determined by single-particle inductively coupled plasma mass spectroscopy for speciation of the dominant AgCNPs. AgCNPs were detected in all five soil samples with the concentrations of 0.23-8.00 × 107 particles/g and sizes of 16-110 nm. Ag2S NPs were the main form of AgCNPs in the examined soils with the percentage range of 53.98-69.19%, followed by AgCl NPs (11.42-23.31%) and Ag NPs (7.78-16.19%). Our method offers a new approach for evaluating the occurrence and potential risk of AgCNPs in environmental soils.