Water quality's responses to water energy variability of the Yangtze River.

River energy serves as an indicator of pollutant-carrying capacity (PCC), influencing regional water quality dynamics. In this study, MIKE21 hydrodynamics-water quality models were developed for two scenarios, and grid-by-grid numerical integration of energy was conducted for the Yangtze River's mainstream. Comparison of predicted and measured values at monitoring points revealed a close fit, with average relative errors ranging from 5.17 to 8.37%. The concept of PCC was introduced to assess water flow's ability to transport pollutants during its course, elucidating the relationship between river energy and water quality. A relationship model between Unit Area Energy (UAE) and PCC was fitted (R2 = 0.8184). Temporally, reservoir construction enhanced the smoothness of UAE distribution by 74.47%, attributable to peak shaving and flow regulation. While this flood-drought season energy transfer reduced PCC differences, it concurrently amplified pollutant retention by 40.95%. Spatially, energy distribution fine-tuned PCC values, showcasing binary variation with energy changes and a critical threshold. Peak PCC values for TP, NH3-N, and COD were 2.46, 2.26, and 54.09 t/(km·a), respectively. These insights support local utility regulators and decision-makers in navigating low-carrying capacity, sensitive areas, enhancing targeted water protection measures for increased effectiveness and specificity.

Dual-Wave Acoustofluidic Centrifuge for Ultrafast Concentration of Nanoparticles and Extracellular Vesicles.

Extracellular vesicles (EVs) are secreted nanostructures that play various roles in critical cancer processes. They operate as an intercellular communication system, transferring complex sets of biomolecules from cell to cell. The concentration of EVs is difficult to decipher, and there is an unmet technological need for improved (faster, simpler, and gentler) approaches to isolate EVs from complex matrices. Herein, an acoustofluidic concentration of extracellular vesicles (ACEV) is presented, based on a thin-film printed circuit board with interdigital electrodes mounted on a piezoelectric substrate. An angle of 120° is identified between the electrodes and the reference flat of the piezoelectric substrate for simultaneous generation of Rayleigh and shear horizontal waves. The dual waves create a complex acoustic field in a droplet, resulting in effective concentration of nanoparticles and EVs. The ACEV is able to concentrate 20 nm nanospheres within 105 s and four EV dilutions derived from the human prostate cancer (Du145) cell line in approximately 30 s. Cryo-electron microscopy confirmed the preservation of EV integrity. The ACEV device holds great potential to revolutionize investigations of EVs. Its faster, simpler, and gentler approach to EV isolation and concentration can save time and effort in phenotypic and functional studies of EVs.

Spatiotemporal variation of vegetation cover in mining areas of Dexing City, China.

Dexing City is an important mining city in China, abounding in copper ore, lead ore, zinc ore, and other metal resources, and there are two large open-pit mines in its territory, Dexing Copper Mine and Yinshan Mine. The two open-pit mines have been expanding their mining production scale since 2005, with frequent mining activities; and the expansion of the pits and the discharge of solid waste will undoubtedly increase the land use and cause the destruction of vegetation. Therefore, we plan to visualize the change in vegetation cover in Dexing City from 2005 to 2020 and the expansion of the two open-pit mines by calculating changes of the Fractional Vegetation Cover (FVC) in the mining area using remote sensing technology. In this study, we calculated the FVC of Dexing City in 2005, 2010, 2015 and 2020 using data from NASA Landsat Database via ENVI image analysis software, plotted the FVC reclassified maps via ArcGIS, and conducted field investigations in the mining areas of Dexing City. In this way, we can visualize the spatial and temporal changes of vegetation cover in Dexing City from 2005 to 2020, and appreciate the situation of mining expansion and its solid waste discharge in Dexing City. The results of this study showed that the vegetation cover of Dexing City remained stable from 2005 to 2020, as the expansion of mining scale and mine pits was accompanied by active environmental management and land reclamation, setting a positive example for other mining cities.

Mine land reclamation, mine land reuse, and vegetation cover change: An intriguing case study in Dartford, the United Kingdom.

Dartford, a town in England, heavily relied on industrial production, particularly mining, which caused significant environmental pollution and geological damage. However, in recent years, several companies have collaborated under the guidance of the local authorities to reclaim the abandoned mine land in Dartford and develop it into homes, known as the Ebbsfleet Garden City project. This project is highly innovative as it not only focuses on environmental management but also provides potential economic benefits, employment opportunities, builds a sustainable and interconnected community, fosters urban development and brings people closer together. This paper presents a fascinating case that employs satellite imagery, statistical data, and Fractional Vegetation Cover (FVC) calculations to analyse the re-vegetation progress of Dartford and the development of the Ebbsfleet Garden City project. The findings indicate that Dartford has successfully reclaimed and re-vegetated the mine land, maintaining a high vegetation cover level while the Ebbsfleet Garden City project has advanced. This suggests that Dartford is committed to environmental management and sustainable development while pursuing construction projects.

Three gorges dam shifts estuarine heavy metal risk through suspended sediment gradation.

Damming alters downstream sediment supply relationships and erosion in the estuarine delta. Given that sediment grainsize serves as a key parameter for the ability to adsorb heavy metals from water, the assessment of estuarine heavy metal risk needs to get connected initially. Hence, fine suspended sediment (<63 µm) in the Yangtze River estuary (YRE) was divided into four grainsize fractions to simulate the surface suspended sediment concentration (SSC) and grainsize composition before and after the completion of the Three Gorges Dam (TGD). Representative months were selected for flood peak reduction (October) and runoff compensation in the dry season (March) to maximize the scheduling impact of the TGD on runoff and riverine sediment input to the YRE. An improved Water Quality Index (WQI) approach was proposed to assess the combined risk alteration of five heavy metals in six estuarine sensitive targets due to TGD-induced sediment characteristics. The results demonstrated that TGD significantly but tardily reduced the SSC and the proportion of fine sediment in the YRE, decreasing the risk of heavy metals resuspension. Seasonally, the total SSC became higher in the flood season than in the dry season during post-TGD period. However, the fine SSC in the flood season was averaged only 59.7% of that in the dry season due to the pronounced grainsize coarsening effect. As the significant reduction in fine SSC overcomes the increase in heavy metal content per unit of SS, the integrated resuspension risk declined significantly, particularly for Pb and Cr. Spatially, the risk reduction for sensitive targets near the turbidity maximum zone (TMZ) is 8.4 times greater than for inner river channel. However, undiminished anthropogenic metal inputs to the YRE signified greater pressures on the depositional environment.

Experimental study of sediment wash-off process over urban road and its dependence on particle size distribution.

Sediment originating from the urban road runoff is a main contributor to water pollution in urban areas. The size of the road sediment varies significantly, but its influence on sediment wash-off process has not been well investigated. In this study, sediments with different particle size distributions have been used in rainfall-runoff experiments over idealized urban road surface. The results show that, under the same experimental conditions, the capacity factor CF increases with the decrease of the median particle diameter D50, which is the dominant influencing factor on CF. The wash-off coefficient k is affected by both D50 and the grading of sediment. During the wash-off process, D50 of the sediment collected at the outlet increases with time. Such a grain coarsening phenomenon is particularly apparent when the road is originally covered with very fine sediments. Furthermore, the presence of coarse grains slows down the transport of fine sediment whose size is smaller than 14 µm. This shielding effect significantly affects the sediment wash-off process in the early stage of a rainfall event, while later on the interaction between particles of different sizes becomes unimportant. This study advances the understanding of sediment wash-off mechanism on urban road surface.

Water transparency distribution under varied currents in the largest river-connected lake of China.

Water transparency is an important ecological indicator for shallow lakes. The largest shallow lake, Poyang Lake, as well as the most typical river-connected lake in China was selected as the research area. In view of the complicated water-sediment conditions induced by its frequent water exchange with external rivers, the dominant factors driving water transparency were determined against the field investigated data from 2003 to 2013 and a specific driving function was established. A numerical model coupling suspended sediment, Chl-a and chemical oxygen demand was developed and validated, and the spatial water transparency distributions under three typical current structures in Poyang Lake, Gravity-style, Jacking-style and Backflow-style, were quantitatively estimated. The following results stood out: water transparency in the lake varied distinctly with the current status; Backflow-style current was basically characterized by the lowest water transparency, while that under Jacking-style was the highest due to the lower sediment carrying capacity. In some outlying regions in the lake, where the water current is hardly influenced by the mainstream, the water transparency was always kept at a stable level.

Achieving consistency of flexible surface acoustic wave sensors with artificial intelligence.

Flexible surface acoustic wave technology has garnered significant attention for wearable electronics and sensing applications. However, the mechanical strains induced by random deformation of these flexible SAWs during sensing often significantly alter the specific sensing signals, causing critical issues such as inconsistency of the sensing results on a curved/flexible surface. To address this challenge, we first developed high-performance AlScN piezoelectric film-based flexible SAW sensors, investigated their response characteristics both theoretically and experimentally under various bending strains and UV illumination conditions, and achieved a high UV sensitivity of 1.71 KHz/(mW/cm²). To ensure reliable and consistent UV detection and eliminate the interference of bending strain on SAW sensors, we proposed using key features within the response signals of a single flexible SAW device to establish a regression model based on machine learning algorithms for precise UV detection under dynamic strain disturbances, successfully decoupling the interference of bending strain from target UV detection. The results indicate that under strain interferences from 0 to 1160 µÎµ the model based on the extreme gradient boosting algorithm exhibits optimal UV prediction performance. As a demonstration for practical applications, flexible SAW sensors were adhered to four different locations on spacecraft model surfaces, including flat and three curved surfaces with radii of curvature of 14.5, 11.5, and 5.8 cm. These flexible SAW sensors demonstrated high reliability and consistency in terms of UV sensing performance under random bending conditions, with results consistent with those on a flat surface.

Navigating the difference of riverine microplastic movement footprint into the sea: Particle properties influence.

As a critical source of marine microplastics (MPs), estuarine MPs community varied in movement due to particle diversity, while tide and runoff further complicated their transport. In this study, a particle mass gradient that represents MPs in the surface layer of the Yangtze River estuary was established. This was done by calculating the masses of 16 particle types using the particle size probability density function (PDF), with typical shapes and polymers as classifiers. Further, Aschenbrenner shape factor and polymer density were embedded into drag coefficients to categorically trace MP movement footprints. Results revealed that the MPs in North Branch moved northward and the MPs in South Branch moved southeastward in a spiral oscillation until they left the model boundary under Changjiang Diluted Water front and the northward coastal currents. Low-density fibrous MPs are more likely to move into the open ocean and oscillate more than films, with a single PE fiber trajectory that reached a maximum oscillatory width of 16.7 km. Over 95 % of the PVC fiber particles settled in nearshore waters west of 122.5°E. Elucidating the aggregation and retention of different MPs types can provide more accurate environmental baseline reference for more precise MP exposure levels and risk dose of ingestion for marine organisms.

Rubber additives and relevant oxidation products in groundwater in a central China region: Levels, influencing factors and exposure.

This study investigated the presence of rubber additives and relevant oxidation products (RAROPs) in groundwater in central China's aboveground river region. Seven RAROPs were detected, and their levels in shallow groundwater showed a mild decreasing trend from the area near the Yellow River (Avg: 8.49 ng L-1) to the area on the far bank of the Yellow River (Avg: 5.01 ng L-1). In contrast, deep groundwater's RAROPs contents showed a dramatic decrease to only 0.26 ng L-1. The dominant contaminant was found to be N-(1, 3-dimethylbutyl) -N'-phenyl -p-phenylenediamine (6PPD). The vicinity of the garages and car parks was often characterized as contamination hotspots. Correlation analyses further indicated that aquaculture was likely to be a potential pathway for shallow groundwater contaminant inputs. The amount of RAROPs intake by humans through groundwater is nearly 30 times different due to the imbalanced development between urban and rural areas. Children were the most vulnerable to RAROPs. Therefore, human activities (transportation, waste tire storage, water resource allocation and utilization patterns, diversion of Yellow River water to aquaculture ponds) may exacerbate RAROPs pollution in groundwater by leaching contaminants through the surface soil. These results are important for developing appropriate utilization and protection strategies for groundwater resources in developing countries.

Universal Murray's law for optimised fluid transport in synthetic structures.

Materials following Murray's law are of significant interest due to their unique porous structure and optimal mass transfer ability. However, it is challenging to construct such biomimetic hierarchical channels with perfectly cylindrical pores in synthetic systems following the existing theory. Achieving superior mass transport capacity revealed by Murray's law in nanostructured materials has thus far remained out of reach. We propose a Universal Murray's law applicable to a wide range of hierarchical structures, shapes and generalised transfer processes. We experimentally demonstrate optimal flow of various fluids in hierarchically planar and tubular graphene aerogel structures to validate the proposed law. By adjusting the macroscopic pores in such aerogel-based gas sensors, we also show a significantly improved sensor response dynamics. In this work, we provide a solid framework for designing synthetic Murray materials with arbitrarily shaped channels for superior mass transfer capabilities, with future implications in catalysis, sensing and energy applications.

Surface Acoustic Wave-Enhanced Multi-View Acoustofluidic Rotation Cytometry (MARC) for Pre-Cytopathological Screening.

Cytopathology, crucial in disease diagnosis, commonly uses microscopic slides to scrutinize cellular abnormalities. However, processing high volumes of samples often results in numerous negative diagnoses, consuming significant time and resources in healthcare. To address this challenge, a surface acoustic wave-enhanced multi-view acoustofluidic rotation cytometry (MARC) technique is developed for pre-cytopathological screening. MARC enhances cellular morphology analysis through comprehensive and multi-angle observations and amplifies subtle cell differences, particularly in the nuclear-to-cytoplasmic ratio, across various cell types and between cancerous and normal tissue cells. By prioritizing MARC-screened positive cases, this approach can potentially streamline traditional cytopathology, reducing the workload and resources spent on negative diagnoses. This significant advancement enhances overall diagnostic efficiency, offering a transformative vision for cytopathological screening.

Applying water environment capacity to assess the non-point source pollution risks in watersheds.

Comprehension of the spatial and temporal characteristics of non-point source (NPS) pollution risk in watersheds is essential for NPS pollution research and scientific management. Although the concept of water functional zones (WFZ) has been considered in the NPS pollution risk assessment process. However, no comprehensive study of the NPS pollution risk has been conducted to effectively protect water quality in watersheds with different water environment capacity. Therefore, this study proposes a new NPS pollution risk assessment method that integrates water functional zoning, receiving water body environmental capacity, and space-time distribution of pollution load for quantifying the impact of pollution discharge from sub-catchment on nearby water body quality. Based on the NPS nutrient loss process modeled by the Soil and Water Assessment Tool (SWAT), this method was used to assess the NPS pollution risk in the Le 'an River Watershed at annual and monthly scales. The results showed that the NPS pollution risk is characterized by seasonal and spatial variability and is influenced clearly by the water environment capacity. High NPS pollution loads are not necessarily high pollution risks. Conversely, a low NPS nutrient pollution load does not represent a low regional risk sensitivity. In addition, NPS risk assessment based on the water environment capacity could also distinguish the differences in risk levels that were masked by similar NPS pollutant loss and the same water function zoning to achieve accurate control of NPS pollution management in watersheds.

Typhoon triggers estuarine heavy metal risk by regulating the multifractal grainsize of resuspended sediment.

The turbulent boundary layer generated by wind in the estuarine surface water serves as a main factor affecting the distribution of suspended particulate matter (SPM) and suspended sediment concentration (SSC). In this study, representative typhoon-induced variation of surface fine SPM (<63 µm) was simulated in the Yangtze River Estuary (YRE) under two time scenarios. Each scenario contained four grainsize SPM fractions named Fraction 1 (<8 µm), Fraction 2 (8-16 µm), Fraction 3 (16-32 µm), Fraction 4 (32-63 µm). The typhoon-induced resuspended multifractal SSC quantification (TRMSQ) based on the relationship between SPM grainsize and heavy metal adsorption capacity was proposed to assess the variation in the resuspended threat of heavy metal to 6 key estuarine protected objects (three reservoirs & three national reserves) between Scenarios 1 and 2. The results presented that Fraction 3 exhibited the maximum increment in SSC resuspension mass and longest regression time from typhoon. Combined with TRMSQ, chromium (Cr) was calculated to be the riskiest typhoon-induced factor. The integrated resuspended risk of heavy metals for each protected object tends to increase from the northwest of Chongming Island (1.2) towards the maximum turbidity zone (>9) downstream, with an estuary-wide mean of 3.3.

How microplastic loads relate to natural conditions and anthropogenic activities in the Yangtze river basin.

As the third largest river in the world, microplastic pollution in the Yangtze River basin is currently attracting worldwide attention. However, fragmented research information is insufficient to reveal the occurrence and driving mechanisms of microplastics throughout the Yangtze River basin. Building on a systematic review of 20 existing publications, this study constructed a dataset including microplastic data from 366 samples in the Yangtze River basin through a data filtering process, and data on natural conditions and anthropogenic activities from 101 basin municipalities. Further, multivariate statistical analysis was utilized to enhance the understanding of the abundance, composition and drivers of microplastics within the basin. Differences in microplastic abundance among the sampling sites were up to 5 orders of magnitude, with the highest abundance value found in the upstream city of Chengdu. The comprehensive diversity index used to describe the composition characteristics of microplastics ranged from 0.31 to 0.68, slightly higher than the national average. Based on a statistical analysis framework, natural conditions and anthropogenic activities were shown to jointly drive the distribution of microplastics, and the dominant driver shifted between the two with spatial variation. In the upstream, anthropogenic activities dominated by GDP (r = 0.85, P < 0.01) were the main positive factor. In the middle and downstream, natural conditions and anthropogenic activities had comparable driving forces as the stability of natural resistance increased, and both were positively correlated with microplastics. Combining the constructed normalized stepwise linear regression model with GIS spatial analysis, the basin-wide application demonstrated that microplastic pollution in the upstream and delta deserved more attention. After coupling the distance factors, microplastic pollution was concentrated in the middle and downstream of the Yangtze River basin, covering important drinking water sources. This study provided important data support for subsequent targeted microplastic reduction and treatment.

An enhanced tilted-angle acoustic tweezer for mechanical phenotyping of cancer cells.

Acoustofluidic devices becomes one of the emerging and versatile tools for many biomedical applications. Most of the previous acoustofluidic devices are used for cells manipulation, and the few devices for cell phenotyping with a limitation in throughput. In this study, an enhanced tilted-angle (ETA) acoustofluidic device is developed and applied for mechanophenotyping of live cells. The ETA Device consists of an interdigital transducer which is positioned along a microfluidic channel. An inclination angle of 5° is introduced between the interdigital transducer and the liquid flow direction. The pressure nodes formed inside the acoustofluidic field in the channel deflect the biological cells from their original course in accordance with their mechanical properties, including volume, compressibility, and density. The threshold power for fully converging the cells to the pressure node is used to calculate the acoustic contrast factor. To demonstrate the ETA device in cell mechanophenotyping, and distinguishing between different cell types, further experimentation is carried out by using A549 (lung cancer cells), MDB-MA-231 (breast cancer cells), and leukocytes. The resulting acoustic contrast factors for the lung and breast cancer cells are different from that of the leukocytes by 27.9% and 21.5%, respectively. These results suggest this methodology can successfully distinguish and phenotype different cell types based on the acoustic contrast factor.

How the Yangtze River transports microplastic to the east China sea.

Land transportation in the Yangtze River basin is an important source of microplastics in the East China Sea, so it is significant to clarify the source, fate and river-sea transition of microplastics. Taking the Yangtze River as the study area, the interpolation method was used to analyze the monthly changes of the microplastic load in the estuary, the input-output model was used to estimate the flux of microplastics into the sea, and the inflow process of microplastics was studied through correlation analysis. The results showed that: (1) The load of microplastics in the Yangtze River estuary varied with season, reaching the maximum in October, with a monthly load of 3.91 Gg; (2) The total amount of microplastics entering the sea in the Yangtze River basin was higher than the medium level, which was 7.02 Gg. Among them, tributary input was the most important source, accounting for 62.9%. Non-point and point sources were further subdivided into 11 categories, with the largest proportion of microplastics generated during vehicle trip. Spatially speaking, the microplastics transported in the midstream accounted for the largest proportion, accounting for 55.56%; (3) microplastics had a strong correlation with COD and TP, indicating that the inflow process of microplastics was similar to that of traditional pollutants, which were river retention, wastewater treatment plant removal, water consumption removal and inflow to the East China Sea. Although the proportion of the last one was only 8.05%, the ecological risk was still not negligible due to the huge amount.

The fate of microplastics in estuary: A quantitative simulation approach.

Microplastics pollution is an emerging environmental concern. However, there are almost no MPs numerical simulation studies in the Yangtze Estuary which is considered as the largest plastic export in the world and quantitative simulation is not carried out in the existing models. Therefore, completing quantitative simulation and exploring different patterns of MPs transport are the main objectives of this study. In addition, the concentration distribution and risk of MPs are also analyzed. Mass-Number method is proposed to quantitatively simulate microplastics concentration in Feb. and May with errors of less than 18%. Compared with sediment flocculation and settling transport, independent floating transport is more susceptible to surface currents resulting in increased beaching and more inhomogeneous concentration distribution. Meanwhile, under the influence of current, local topography and salt wedge, the MPs perform linear motion and clockwise spiral motion inside and outside the estuary and rapidly form a "hot spot" on the southeastern part of Chongming Island and 57% to 90% of MPs are beached or settled inside the estuary, especially on the north shore. Therefore, MPs risk in some sensitive targets should be concerned according to risk assessment results. Our results break the space-time limit and explore the fate of MPs in the Yangtze Estuary and provide new idea and concern of MPs numerical simulation.

How climate change and land-use evolution relates to the non-point source pollution in a typical watershed of China.

The water quality of Le 'an River Watershed (LRW) is crucial to the water environmental safety of Poyang Lake, especially the concentration of nitrogen and phosphorus. The effect of climate and land use change on watershed water quality has always been under the attention of local managers. More importantly, the lack of detailed studies on climate and land use impact on river water quality has prevented sustainable water security management in the LRW. Therefore, this study aimed to quantify the weight of climate and land use on nutrient loss in the LRW, respectively. We divided the historical period (1990-2020) into six scenarios and a baseline scenario. TN and TP losses in the watershed were simulated using Soil and Water Assessment Tool (SWAT), and the weight of climate and land use were quantified in overall, by period, and by region. The results showed that the weight of climate was greatly higher than land use with values around 90%. However, the weight of land use had a positive cumulative effect in a certain period, and its influence could not be neglected. The climate in all scenarios led to a reduction in nutrient loss, while land use was found to slightly increase the nutrient loss yield. In addition to, unique regional topographic features, urbanization rates, and climatic conditions could cause spatial heterogeneity in the climatic and land use weights.