Nanoparticle facilitated inhalational delivery of erythropoietin receptor cDNA protects against hyperoxic lung injury.

Our goals were to develop and establish nanoparticle (NP)-facilitated inhalational gene delivery, and to validate its biomedical application by testing the hypothesis that targeted upregulation of pulmonary erythropoietin receptor (EpoR) expression protects against lung injury. Poly-lactic-co-glycolic acid (PLGA) NPs encapsulating various tracers were characterized and nebulizated into rat lungs. Widespread NP uptake and distribution within alveolar cells were visualized by magnetic resonance imaging, and fluorescent and electron microscopy. Inhalation of nebulized NPs bearing EpoR cDNA upregulated pulmonary EpoR expression and downstream signal transduction (ERK1/2 and STAT5 phosphorylation) in rats for up to 21 days, and attenuated hyperoxia-induced damage in lung tissue based on apoptosis, oxidative damage of DNA, protein and lipid, tissue edema, and alveolar morphology compared to vector-treated control animals. These results establish the feasibility and therapeutic efficacy of NP-facilitated cDNA delivery to the lung, and demonstrate that targeted pulmonary EpoR upregulation mitigates acute oxidative lung damage. FROM THE CLINICAL EDITOR: Acute lung injury often results in significant morbidity and mortality, and current therapeutic modalities have proven to be ineffective. In this article, the authors developed nanocarrier based gene therapy in an attempt to upregulate the expression of pulmonary erythropoietin receptor in an animal model. Inhalation delivery resulted in reduction of lung damage.

High-throughput absolute quantification sequencing reveals the adaptive succession and assembly pattern of plastisphere communities in municipal sewer systems: Influence of environmental factors and microplastic polymer types.

Municipal sewer systems have received increasing attention due to the magnitude of the microplastic stock and its potential ecological impacts. However, as a critical aspect of the adverse impacts, little is known about the plastisphere that forms in these engineered environments. Using high-throughput absolute quantification sequencing, we conducted a systemic study combining field survey and laboratory batch test to explain the general plastisphere pattern and the role of environmental and polymeric factors in driving plastisphere succession and assembly there. We demonstrated the capacity of microplastics to support high levels of microbial colonization, increasing by 8.7-56.0 and 1.26-5.62 times at field and laboratory scales, respectively, despite the less diverse communities hosted in the resulting plastisphere. Sediment communities exhibited higher diversity but greater loss of specific operational taxonomic units in their plastisphere than in the wastewater. The former plastisphere had primarily an enhanced methanogenesis-oriented metabolic network linked to hydrolysis fermentation, hydrogen-producing acetogenesis, and denitrification, while the latter had a pronounced niche partitioning and competitive interaction network. Exogenous substrate flux and composition were key in stimulating plastisphere community growth and succession. Furthermore, the high nitrogen baseline facilitated alternative niche formation for plastisphere nitrifiers and denitrifiers, and the plastisphere pathogens associated with denitrification and plastic biodegradation functions increased significantly. The aerobic state also promoted a 1.71 times higher colonizer load and a denser interaction pattern than the anaerobic state. Selective filtering by polymers was evident: polyethylene supported higher plastisphere diversity than polypropylene. This study provides new insights into the mechanisms driving colonizer loads and the adaptive succession and assembly of the plastisphere in such a typically hydrodynamic and highly contaminated environment. The results help to fill the knowledge gap in understanding the potential role of microplastics in shaping the microecology of sewers and increasing health risks and substrate loss during sewer transfer.

Land use, stratified wastewater and sediment, and microplastic attribute factors jointly influence the microplastic prevalence and bacterial colonization patterns in sewer habitats.

The capacity of microplastics to harbor and propagate bacteria has been the focus of attention over the last decade. Such microplastic-supported bacterial colonization behavior in the municipal sewer system could be a critical ecological link influencing the biogeochemical activities and risks in receiving waters in urban areas, given the alarming microplastic loads discharged there. This study conducted a large-scale survey covering a wide range of residential and industrial catchments in Shanghai, China. We aimed to assess the microplastic prevalence and bacterial colonization patterns in different sewer habitats and to explore the role of land use, stratified wastewater and sediment, and microplastic attributes in shaping the patterns. We found that the sewer system formed a temporal but pronounced microplastic pool, with land use playing a significant role in the variability of microplastic prevalence. Industrial sewers contained a high abundance of microplastics with large particle sizes, diverse polymer compositions, and shapes. However, while there was a spatial discrepancy between urban and suburban areas in the abundance of microplastics in residential sewers, their predominant polymer and shape types were simple, i.e., polyethylene terephthalate (PET) and fibers. Sewer habitat characteristics, particularly the stratified wastewater and sediment determined microbial colonization patterns. The latter acted as a long-term sink for microplastics and supported the high growth of colonizers. In contrast, the wastewater plastisphere presented novel niches, hosting communities with a marked proportion of unique bacterial genera after colonization. Besides, statistics showed a highly positive and dense co-occurrence network of the plastisphere communities, especially those from the industrial sewer sediment, with enhanced metabolic activity, cellular processes and systems, and increased human pathogenic potential. Findings indicated a coarse and uncertain effect of the selective pressure of microplastic attributes on plastisphere community structure differentiation.

Real-time variabilities in microplastic abundance and characteristics of urban surface runoff and sewer overflow in wet weather as impacted by land use and storm factors.

Urban surface runoff (USR) and drainage system overflows during wet weather (WWF) play a key role in shaping water pollution. Particularly, the impact of large amounts of microplastic pollution on urban water bodies is unclear. We conducted an in-field investigation in six central urban drainage systems along Suzhou Creek in the Shanghai megacity of China and identified the impacts of storm factors and land use on the real-time dynamic changes in microplastic abundance and characteristics in USR and WWF. Microplastic abundances ranged from 228.3 ± 105.4-4969.51 ± 348.8, 309.3 ± 144.3-5195.8 ± 425.5, and 130.0 ± 30.0-8500.0 ± 1241.0 particles/L in the traffic and residential catchment USR, and the WWF, respectively. Under similar storm factor conditions, we observed correlations between environmental factors and microplastic abundance, especially the polymer type, verifying the significant role of land use. The microplastic abundance were 90.2 particles/L higher in the traffic catchment USR than in the residential catchment USR. Notably, we found unique microplastic polymers comprising ethylene vinyl acetate copolymer and thermoplastic elastomers in the residential and traffic catchment USR, respectively. However, land use had a minimum impact on the size and shape of microplastics: small-sized and film microplastics dominated in both USR types. We found statistical evidence of the widespread correlations between microplastic abundance and storm factors (accumulated storm depth and WWF flow) in both USR and WWF. The first flush phenomenon of microplastic dynamics was found in both USR and WWF. Microplastic characteristics also changed dynamically with storm time. With heavy storm factors, polypropylene and small-sized (<1 mm) microplastics in USR events increased and then decreased. This was also true for WWF events in granular and polyethylene terephthalate microplastics. Our results can facilitate the targeted mitigation of emerging pollutants to enhance stormwater management strategies and prevent future contamination.

[Ecological Risk Assessment of Microplastics Occurring in Surface Water of Terrestrial Water Systems across China].

To assess the ecological risk of microplastics (MPs) occurring in the surface water of terrestrial water systems across China, this study obtained relevant literature and data by searching keywords including microplastics, urban, and river on websites such as Science Direct and Web of Science. We constructed an evaluation method of ecological risk characterization ratio (RCR) based on chemical hazard data, as well as data of MPs abundance and polymer proportion originating in studies from 2017 to 2021 that covered 33 water bodies in 15 provinces. The results showed that the average abundance of MPs in natural water bodies in China reached (3604.2±5926.4) n·m-3, and the average abundance of MPs in urban water bodies was (7722.6±9505.7) n·m-3. The corresponding average RCR of natural water bodies was 22.09±45.2, and the average RCR of urban water bodies was 15.67±34.8. Therefore, according to the value of RCR, the ecological risk could be rated as four levels. Of these, no significant risk (RCR ≤ 1) was found in 17 water bodies, accounting for 42.5%; low ecological risks (RCR 1-10) were found in 12 water bodies (30%); medium ecological risks (RCR 10-100) were found in 9 water bodies (22.5%); and high ecological risks (RCR>100) were found in 2 water bodies (5%). Data analysis showed a significant correlation between MPs abundance and RCR values in natural water bodies (R2=0.875, P<0.01), though not in urban water bodies. This suggested that the high abundance of MPs could not precisely indicate a high degree of ecological risk in the area. In addition, RCR values were observed to be positively correlated with the watershed area (R2=0.864, P<0.01), and MPs abundance was correlated with GDP (R2=0.679, P<0.05) and watershed resident population (R2=0.922, P<0.05). This study provides baseline data for evaluating the ecological risk of MPs and a feasible method for evaluating the ecological risk of MPs in surface water of terrestrial water systems.

Quantifying microplastic stocks and flows in the urban agglomeration based on the mass balance model and source-pathway-receptor framework: Revealing the role of pollution sources, weather patterns, and environmental management practices.

Microplastics are widely present in global ecosystems, threatening both marine and freshwater species. Given this problem, it is vital to research where land-based microplastics originate and how they are transmitted to receiving waters in urban agglomerations. Research results should inform systemic mitigation efforts to prevent future contamination. This study established the multi-directional transmission network of a microplastic mass balance system using a source-pathway-receptor framework, and involving annual source stocks and pathway flows with considerable variations under dry and wet weather patterns. Details of a baseline scenario quantifying the occurrence and spread of microplastics in an urban agglomeration were also determined in the context of current environmental management practices. We demonstrated that the total stock of the six major pollution sources amounted to 5317.7 ± 2175.3 and 3320.1 ± 953.6 tons/a in dry and wet weather, respectively; and 2347.8 ± 766.9 and 1991.8 ± 701.8 tons/a flows directly entered the sewer system and receiving water in Shanghai, China, respectively. Prominent microplastic stocks were found in atmospheric fallout, industrial wastewater, and domestic sewage. These stocks were much higher compared to crop farming wastewater, aquacultural wastewater, and livestock and poultry breeding wastewater. Total microplastic flows entering receiving water reached 3207.4 ± 1071.6 tons/a; the largest contributions were from wet weather overflow (23.7%), direct atmospheric fallout (21.7%), wastewater treatment plant effluent (14.2%), industrial wastewater (14.1%), and surface runoff (10.4%). Weather patterns led to divergent microplastic transmission pathways and mass flows, revealing a lagging timeline mode and illustrating the basic spatiotemporal features of microplastic contamination in urban agglomerations. Terminal disposal practices retained about two-fifths of the microplastic flows that would have otherwise been transmitted into receiving water. Of these, land surface sweep contributed half of the retained flow. Improvements in WWTP removal efficiency, storm sewage interception rate, industrial wastewater collection rate, and sewer sediment dredge rate could further enhance the systemic benefits.

A neglected transport of plastic debris to cities from farmland in remote arid regions.

Although microplastics have been investigated in terrestrial environments, the occurrence and transport of microplastics in semiarid regions with serious wind erosion are still limited. We investigated plastic debris, including macroplastics (>5 mm) and microplastics (50 µm to 5 mm), from twenty semiarid farmlands and then developed a mass flux model to calculate the quantities of plastic debris transport by wind erosion. Finally, the spatial extent of microplastic deposition was estimated. The average abundance of macroplastics increased with duration of mulching film use, whereas the abundance of microplastics did not change significantly (p > 0.05). Moreover, the highest abundance of microplastics among samples was from the farmland using greenhouse, which suggests that wind erosion played an essential role in retention of plastic debris. Besides, the enrichment ratio (ER) which depends on the shape of microplastics is identified to be a key indicator of the mass flux model. The results showed that 6.91-38.11 kg/ha of plastic debris was released by wind in the 25th year after film application, with 6.14 n/m2 of microplastics settling in February in Xi'an, which is 690 km away from the source.

The occurrence of microplastics in water bodies in urban agglomerations: Impacts of drainage system overflow in wet weather, catchment land-uses, and environmental management practices.

The footprints of microplastics in the water bodies of urban agglomerations are largely dominated by superimposed anthropogenic influences. Understanding these influences and how they are correlated is essential to better understand the occurrence and variability of microplastics in different ecosystems. This study longitudinally assessed the abundance and distribution of microplastics in the water bodies of urban agglomerations at the watershed-scale in Shanghai Megacity. Particularly, the behavior of microplastics with the impacts of drainage system overflow in wet weather (WWF), land uses, and environmental management practices were explored. WWF can greatly aggravate microplastic pollution in aquatic environments. A systemic estimation based on detailed data was used to show that the annual load of microplastics discharged via WWF in the watershed area was 8.50 × 1014 p/year, which was approximately six times larger than that discharged via the local Wastewater Treatment Plant effluent. Findings here contribute to research concerning the spatial variability of aquatic microplastics and the extent to which they are affected by land use. In descending order, the highest microplastic concentrations were found in heavy industrial > commercial/public/recreational > agricultural/light industrial > agricultural > and residential areas. The longitudinal pattern of microplastics observed in the water bodies suggested that there were superimposed effects of land use and hydrodynamics. This paper is the first to provide an integrated framework that demonstrates the significant role of environmental management practices in controlling the production and transmission of microplastics to receiving waters at a city-scale. Improved management of WWF might be a tangible solution that would help achieve an immediate and large-scale reduction of microplastics in sewage. Determining the optimized management practices for different weather or hydrological conditions could be an essential factor in decreasing microplastic concentrations and altering their flow-path pattern in a given region.

[Pollution Status and Pollution Behavior of Microplastic in Surface Water and Sediment of Urban Rivers].

Rivers have been a subject of great concern in recent years as they have been found to be the critical path for the transmission of microplastics from terrestrial land to the ocean. However, the pollution status of microplastics and their behavior in the surface waters and sediments of urban rivers located in different urban areas remain unclear. In this study, 16 samples of surface water and sediment from eight rivers in the central and suburban areas of Shanghai Megacity were obtained and analyzed. High-speed cameras and Fourier transform infrared spectrometers were used to identify the abundance, size, color, shape, type, and other characteristics of microplastics in these samples. The results showed that the average abundance of microplastics in the surface waters of urban rivers in Shanghai Megacity was (7.5±2.8) pieces·L-1, while the corresponding average abundance in the sediment reached (1575.5±758.4)pieces·kg-1 (wet weight). The abundance of microplastics was found to increase with the decreasing particle diameter. Among which, microplastics with a size of less than 500 µm, as well as the fibrous shape, transparent color, and Polyester composition, have always dominated in the urban rivers in Shanghai megacity. Comparably, microplastics in the sediments were more diverse in their morphology features and polymer compositions. Microplastic pollution in the urban rivers in Shanghai megacity was severe in comparison to that in other urban rivers worldwide. Among various urban rivers, the distribution of microplastics with different morphology features and polymer compositions is greatly influenced by a number of factors including the source (e.g., mainly laundry wastewater, personal care products, and refuse plastic waste), hydrodynamic conditions, and the physical and chemical properties of plastics. Furthermore, the pollution behavior (i.e., source, transmission, and fate) of microplastics occurring in urban rivers is discussed, and the potential impacts of various environmental factors are explained.