Probabilistic risk assessment of microplastics in Tai Lake, China.

Microplastics are a global environmental concern, especially in freshwater ecosystems. Despite the studies in specific regions of Tai lake, a gap persists in understanding the comprehensive risk of MPs across the entire watershed. Therefore, this study offers an overview of MPs abundance and assesses ecotoxicological risk by employing acute and chronic species sensitivity distributions, which consider the effects triggered by MPs. The concentrations of MPs ranged from 0 to 18.6 particles/L within the lake, 1.56 to 1.42 × 102 particles/L in the rivers, and 0.16 to 0.7 particles/L in the estuaries. Certain areas, particularly the northwest and southeast regions, exhibit higher concentrations. Using existing toxicity data, this study calculated predicted no effect concentrations for acute and chronic exposure of MPs to freshwater species, resulting in values of 11.5 and 31.72 particles/L, respectively. The probabilistic risk assessment indicates that the average risk possibility of MPs in Tai lake was 16 %. Moreover, the risk characterization ratio indicated that 22 % of the locations in Tai lake showed an acute ecological risk, while 7.4 % exhibit a chronic ecological risk. The assessment concluded that MPs reported in the literature could pose a considerable risk to Tai lake biota. However, the risk associated with MPs followed descending order: river >lake > estuary waters. Our research supplies valuable insights for the assessment of ecological risks associated with MPs on a whole watershed scale.

Impacts of environmental flow regulation on survival of aquatic organisms: a case study of Cyprinus Carpio in Baiyangdian, China.

Decreasing water volume and increasing pollutants in wetlands pose challenges to aquatic life. While environmental flow regulation is widely applied to enhance aquatic habitats, its effectiveness needs to be evaluated. In this study, a hydrodynamic-water quality model was used to simulate the fields of flow, temperature, and pollutants. The Ecological Niche Modeling at the MetaLand EcologyLab (ENMTML) was utilized to evaluate the area of suitable habitats for aquatic organisms under both environmental flow regulation and no environmental flow regulation conditions. The typical Baiyangdian Wetland in northern China was taken as the study area, and the important economic fish, Cyprinus carpio, served as the indicator of aquatic species. The effectiveness of environmental flow regulation was evaluated from December 1, 2017, to June 30, 2018. The results indicated that the variables of water depth, dissolved oxygen (DO), ammonia nitrogen (NH4+-N) and Chlorophyll a (Chla) were the major environmental factors determining the variability of the suitable habitat area for Cyprinus carpio. The environmental flow regulation capacity of the Baiyangdian Wetland was 2.6 [Formula: see text] 108 m3, which produced a suitable habitat area of 135.538 km2 at the end of the water supply period. Compared with the no environmental flow regulation condition, the highly and moderately suitable habitat areas for Cyprinus carpio were enlarged by 56.30 km2 and 34.11 km2, respectively. The outcome provides not only a basic reference for wetland management, but also a scientific perspective for understanding the impact of environmental flow regulation on aquatic organisms. The proposed method demonstrates the important potential of evaluating the effectiveness of environmental flow regulation on aquatic organisms in wetlands.

Recent progress of microplastic toxicity on human exposure base on in vitro and in vivo studies.

Microplastics are widely distributed in the environment, including the atmosphere, soil and water bodies. They have been found to have toxic effects on organisms. The impact on human health is also receiving considerable attention. Microplastics can be found in drinking water, food, air and plastic products, and they can enter human body through the pathways such as ingestion, inhalation, and skin contact. After exposure to microplastics, they can induce cellular toxicity and produce toxic effects on multiple organs and systems, including the digestive, respiratory, nervous, reproductive and cardiovascular systems. This paper presents a comprehensive review and analysis on the recent progress of human exposure studies, in vitro experiments, rodent experiments, and other model experiments in microplastic human toxicity research. It comprehensively analyzes the potential human toxic effects of microplastics, providing a theoretical basis for further research on microplastic human toxicity and its mechanisms. Furthermore, this paper highlights the knowledge gaps and provides the recommendations for future research on human toxicity of microplastics.

Modeling the effect of fish migration on the horizontal distribution of microplastics in freshwater and ecological risks in the food web: Influence of habitat.

Microplastics (MPs < 5 mm) pollution is a widespread phenomenon in freshwater ecosystems. While the role of physiochemical factors in the migration and distribution of MPs is understood, the impact of biological migration remains less clear. The influence of nekton migration determined by habitat suitability on the distribution of MPs and the consequent ecological risks to the regional food web is investigated in the freshwater environment by using Baiyangdian Lake (China) as a case study. The key findings reveal that fish migration significantly alters the horizontal distribution of MPs in the water environment, with a higher degree of fish aggregation in high suitability habitats leading to an increased presence of MPs due to their ingestion and excretion behaviors. In both high and low suitability habitats, MPs are found to bioconcentrate in fish, suggesting a significant risk to aquatic ecosystems. Despite the lack of evidence supporting MPs biomagnification, the results indicate that MPs are more likely to be biomagnified within the food web of high suitability habitats due to the enhanced foraging capabilities of aquatic organisms. These findings highlight the critical need to consider biological factors, such as nekton migration, in understanding and addressing MPs pollution in freshwater ecosystems.

Microplastics in Tai lake food web: Trophic transfer and human health risk assessment.

Although microplastics (MPs) in marine organisms have been widely studied, the toxicity of MPs in freshwaters and human health is still a global challenge. To fill this gap, we implemented an Ecopath and food web accumulation model to simulate the Tai Lake ecosystem, a region dependent on the tourism and seafood industries. Our results suggested the accumulation of MPs throughout the food web and ultimately reach organisms at high trophic levels, including human-being, who consume MPs through seafood. The adults were prone to consume more MPs than adolescents and children. Unlike clams, fish biota magnification factors indicated that MPs accumulation between specific predator-prey interactions is not expected. The abundance of MPs within clams reveals a potential risk of MPs entering the food web. To better understand the MPs transfer, we recommend paying greater attention to species-specific mechanisms and the resources they rely on.

Spatial distribution of microplastics in Chinese freshwater ecosystem and impacts on food webs.

Over the past two decades, there has been a lot of discussion about the rapid increase of microplastics (MPs) due to their persistence, ubiquity, and toxicity. The widespread distribution of MPs in various freshwater ecosystems makes them available for different trophic levels biota. The ingestion and trophic transfer of MPs may induce potential impacts on freshwater food webs. Therefore, this systematic review is an in-depth review of 51 recent studies to confirm the spatial distribution of MPs in the Chinese freshwater ecosystem including water, sediment and biota, exposure pathways, and impacts on freshwater food webs. The result suggested the white, transparent and colored, Polypropylene (PP) and Polyethylene (PE) of <1 mm fibers were dominant in Chinese freshwaters. The uptake of MPs by various freshwater organisms as well as physiological, biological and chemical impacts on food webs were also elucidated. At last, some limitations were discussed for future studies to better understand the effects of MPs on food webs.

Study of water quality response to water transfer patterns in the receiving basin and surrogate model.

The spatio-temporal response of water quality in the receiving basins to water transfer remains unclear when considering more practical factors. Moreover, a much fast surrogate model is highly required to realize the purpose of rapid prediction of water quality. In this study, a two-dimensional hydrodynamic and water quality model was primarily established by considering the most comprehensive important pollution sources so far to investigate the water quality variation in Baiyangdian Lake, China. The pollution sources include atmospheric deposition, sediment release, village and tourism domestic sewage, livestock breeding, rainfall runoff, aquatic plants, and animals. The water quality at different sample sites was assessed using the water quality index (WQI). Subsequently, a surrogate model was proposed using the nonlinear autoregressive network with exogenous inputs (NARX), and the NARX model can realize fast prediction of the annual time series of water quality in a few seconds. The results showed that there are significant differences in water quality at different sample sites in each season. The highest WQI value occurred in autumn (65.46), and the average values at different sample sites were between 47.54 and 58.22 in this season. The water quality at Nanliuzhuang site and Caiputai site was significantly affected by water transfer patterns. In addition, the correlation coefficient R2 between the predicted results and the simulated ones except that of parameter TP was larger than 0.90. The prediction performance of surrogate model was shown to be very high efficiency and accurate. The proposed models and the results of this approach are guiding significance for lake management.

Probabilistic health risk assessment of exposure to carcinogens of Chinese family cooking and influence analysis of cooking factors.

Cooking oil fume (COF) have adverse health effects for people. A probabilistic health risk assessment model with risk parameters as random variables considering the differences in exposure concentration and exposure time of different cooking event was proposed to assess the inhalational incremental lifetime cancer risk (ILCR). The exposure of carcinogens such as benzene, formaldehyde, PM2.5-bound polycyclic aromatic hydrocarbons (PPAHs) and PM2.5-bound heavy metals (PHMs) of Chinese family cooking was studied and the exposure concentrations of carcinogens were predicted by computational fluid dynamics (CFD). In addition, the influence of five key cooking factors (cooking method, the weight of ingredients (meat and vegetables), type of meat, ratio of meat to vegetables, and type of oil) that affect the generation of COF was explored. The ILCR of COF is assessed comprehensively in present study by the probabilistic health risk assessment model. The result showed that the sum of the risks of assessed carcinogens (total ILCR of COF) determined by Monte Carlo simulation method with a 95% confidence interval (95%CI) is 2.45 × 10-4 to 1.61 × 10-3, which far exceeds the acceptable limit of 1.00 × 10-6. Generally, the ILCR of assessed carcinogens decreases in the following order: PHMs [ILCR (95%CI): 2.08 × 10-4 to 1.54 × 10-3] > formaldehyde [ILCR (95%CI): 9.04 × 10-6 to 6.87 × 10-5] and PPAHs [ILCR (95%CI): 5.97 × 10-6 to 4.51 × 10-5] > benzene [ILCR (95%CI): 2.99 × 10-7 to 3.00 × 10-6]. The results indicated that more attention should be paid to the ILCR of PM2.5. Cooking method significantly affect the ILCR of carcinogens in COF excluding formaldehyde. The ILCRs of COF from water-based cooking methods are greater than those of oil-based cooking ones.

An innovative approach to identify environmental variables with conservation priorities in habitat patches.

Conservation of habitat patches and the related environment benefits both the focal species and human well-being. Many indices use the dispersal range to identify habitat patches with conservation priorities. However, there lacks approaches to identify environmental variables with conservation priorities (noted as target variables) in those identified patches. Therefore, this paper proposes an approach to identify environmental variables with conservation priorities in habitat patches using perception range and introduces the related assumption. It is assumed the agents select habitats based on their prior preference and perceived information in their perception ranges, which avoids the omniscient assumption of agents. Based on such assumptions, the proposed approach identifies the target variables by approximating how animals identify their habitats. It highlights the use of perception range and identifies target variables using the maximum information gain. The variables that contribute the largest reduction of uncertainty are regarded as the target variables in the habitat patches. Taking the Common Moorhen (Gallinula chloropus) living in Tianjin, China as the case, different scenarios with 100 m, 250 m and 500 m perception ranges are designed to illustrate the feasibility of the proposed approach. The proposed approach identifies the normalized vegetation index, rather than the distance to water surface, is the target variable in 42.3%, 58.9% and 72.1% habitat patches with given perception ranges. Adjustments are made on areas within the given perception range of each patch. More grid cells that has increased suitability index can be found in scenarios given 250 m perception range, which indicates the conservation area is not always the large the better. Optimizations are expected on both a better approximation method and a more thorough hypothesis of using perception range.

Modelling the accumulation of microplastics through food webs with the example Baiyangdian Lake, China.

Microplastic plastics (MPs) is an increasingly widely serious global environment problem, which severely threats aquatic organisms and even human beings. However, the potential change trend of MPs abundance over time in natural aquatic ecosystems and the cumulative effects through food webs are unclear. In this research, the model of accumulation effect of MPs through aquatic food webs was established in the example Baiyangdian Lake (China) using the contaminant tracer module Ecotracer in the Ecopath modelling software. The results indicated that the MPs spread and accumulate throughout the food-web fast, and finally to the high trophic level aquatic organisms, Snakehead. The abundance of MPs in aquatic environment and organisms varies periodically with rainfall. The abundance of MPs in snakehead, mandarin fish, common carp, crucian carp, chub, fingerling, grass carp, mollusc, microzoobenthos, zooplankton increased about 3.97, 2.87, 2.35, 1.8, 1.48, 1.8, 1.86, 1.98, 1.99, 3.49 times of the initial abundance of MPs in them, respectively. Since snakehead exists in the highest trophic level in Baiyangdian Lake ecosystem, the cumulative effect of MPs is the most serious through food web. Furthermore, the accumulation of MPs in different trophic levels has a time delay effect, and the higher the nutrient level is, the more obvious the delay effect is. The results also showed that Ecotracer is a good model to explore the enrichment effect of MPs in food web, the accumulation of MPs through food webs is serious, and the phenomenon should arouse serious attention.

Effect of fine structure of chitosan-based flocculants on the flocculation of bentonite and humic acid: Evaluation and modeling.

The fine molecular structure of a flocculant fundamentally determines the internal flocculation mechanism and the final application property. In this work, three series of chitosan-based polymers (CTS-g-PAMD) with divergent charge densities and graft chain distribution were synthesized by graft copolymerization using acrylamide (AM) and acryloyloxyethyltrimethylammonium chloride (DAC). Meanwhile, flocculant with linear chain structure (CTS-CTA) was prepared by etherification using 3-chloro-2-hydroxypropyltrimethylammonium chloride (CTA). The characterization results confirmed that various monomers had been successfully introduced into chitosan. The reaction basically happened on -NH2 at C2 of chitosan, and the ring structure of chitosan was destroyed by free radical reaction. The obtained flocculants were used to flocculate bentonite and humic acid solution. Besides dose, the effects of chain structure, charge density and chain distribution on flocculation performance were systematically studied. Based on the fractal theory and flocculation kinetics, the effects of structural factors on floc characteristics were also investigated. The results showed that, flocculant with abundant graft chains exerts better flocculation performance and floc characteristic due to enhanced adsorption electrical neutralization and adsorption bridging effect. The effects of charge density and chain distribution on the flocculation performance were disparate in the range of insufficient and excessive doses. Furthermore, on the basis of the quadratic polynomial model, quantitative structure-effect relationships were established, which has guiding significance for the development and utilization of flocculants.

Establishment of urban waterlogging pre-warning system based on coupling RBF-NARX neural networks.

The optimal layout of low-impact development (LID) facilities satisfying annual runoff control for low rainfall expectation is not effective under extreme rainfall conditions and urban waterlogging may occur. In order to avoid the losses of urban waterlogging, it is particularly significant to establish a waterlogging early warning system. In this study, based on coupling RBF-NARX neural networks, we establish an early warning system that can predict the whole rainfall process according to the rainfall curve of the first 20 minutes. Using the predicted rainfall process curve as rainfall input to the rainfall-runoff calculation engine, the area at risk of waterlogging can be located. The results indicate that the coupled neural networks perform well in the prediction of the hypothetical verification rainfall process. Under the studied extreme rainfall conditions, the location of 25 flooding areas and flooding duration are well predicted by the early warning system. The maximum of average flooding depth and flooding duration is 16.5 cm and 99 minutes, respectively. By predicting the risk area and the corresponding flooding time, the early warning system is quite effective in avoiding and reducing the losses from waterlogging.

Effects of chef operation on oil fume particle collection of household range hood.

Kitchen range hood is used to remove cooking oil fume in most of family. The oil fume collection efficiency of range hood is demand to be improved for reaching healthy indoor air quality in residential kitchen. The effects of chef disturbance intensity on the fume particle collection of range hood are quantified by computational fluid dynamics (CFD) model. The chef operation is considered by introducing a moving momentum source where the collection efficiency of fume particle is defined by the particle residence time. The collection efficiency of fume particle is proposed to be classified as the primary collection efficiency and the secondary collection efficiency of fume particle. The results indicate that the primary collection efficiency of fume particle is decreased by 26.4% in vertical disturbance (VD) mode of chef stirring with the rotation velocity from 0 to 1.5 rps. Meanwhile, the primary collection efficiency is decreased by 8.5% in horizontal disturbance (HD) mode for the same range of the rotation velocity of chef stirring. It is further found that the secondary collection efficiency of fume particle can be used as an indicator of the fume particle concentration of kitchen.

Identification of indoor contaminant source location by a single concentration sensor.

Methods of maximum correlation coefficient (MCC) and the minimum discrete degree (MDD) are developed to identify the location of indoor contaminant source. These two methods are simple, effective, and economic due to the need of only one sensor. The methods are validated by a three-dimensional case study. The effects of the sampling time, the sampling interval, and the sensor response time and measurement error on the location identification of the contaminant source are analyzed. The results indicate that the identification performance of the MDD method is better than that of the MCC method; however, the MDD requires a fast response and high-accuracy sensor. MCC method not only has smaller effects of response time and measurement error compared with the MDD method but it also does not require high-performance (accuracy) sensor and it is not suitable for fast identification in a short time. For source location identification, the two methods need to properly choose sampling time, sampling interval, and response time.

Enhanced biodegradation of alkane hydrocarbons and crude oil by mixed strains and bacterial community analysis.

In this study, two strains, Acinetobacter sp. XM-02 and Pseudomonas sp. XM-01, were isolated from soil samples polluted by crude oil at Bohai offshore. The former one could degrade alkane hydrocarbons (crude oil and diesel, 1:4 (v/v)) and crude oil efficiently; the latter one failed to grow on alkane hydrocarbons but could produce rhamnolipid (a biosurfactant) with glycerol as sole carbon source. Compared with pure culture, mixed culture of the two strains showed higher capability in degrading alkane hydrocarbons and crude oil of which degradation rate were increased from 89.35 and 74.32 ± 4.09 to 97.41 and 87.29 ± 2.41 %, respectively. In the mixed culture, Acinetobacter sp. XM-02 grew fast with sufficient carbon source and produced intermediates which were subsequently utilized for the growth of Pseudomonas sp. XM-01 and then, rhamnolipid was produced by Pseudomonas sp. XM-01. Till the end of the process, Acinetobacter sp. XM-02 was inhibited by the rapid growth of Pseudomonas sp. XM-01. In addition, alkane hydrocarbon degradation rate of the mixed culture increased by 8.06 to 97.41 % compared with 87.29 % of the pure culture. The surface tension of medium dropping from 73.2 × 10(-3) to 28.6 × 10(-3) N/m. Based on newly found cooperation between the degrader and the coworking strain, rational investigations and optimal strategies to alkane hydrocarbons biodegradation were utilized for enhancing crude oil biodegradation.

Influence factors and prediction of stormwater runoff of urban green space in Tianjin, China: laboratory experiment and quantitative theory model.

The effects of limiting factors such as rainfall intensity, rainfall duration, grass type and vegetation coverage on the stormwater runoff of urban green space was investigated in Tianjin. The prediction equation of stormwater runoff was established by the quantitative theory with the lab experimental data of soil columns. It was validated by three field experiments and the relative errors between predicted and measured stormwater runoff are 1.41, 1.52 and 7.35%, respectively. The results implied that the prediction equation could be used to forecast the stormwater runoff of urban green space. The results of range and variance analysis indicated the sequence order of limiting factors is rainfall intensity > grass type > rainfall duration > vegetation coverage. The least runoff of green land in the present study is the combination of rainfall intensity 60.0 mm/h, duration 60.0 min, grass Festuca arundinacea and vegetation coverage 90.0%. When the intensity and duration of rainfall are 60.0 mm/h and 90.0 min, the predicted volumetric runoff coefficient is 0.23 with Festuca arundinacea of 90.0% vegetation coverage. The present approach indicated that green space is an effective method to reduce stormwater runoff and the conclusions are mainly applicable to Tianjin and the semi-arid areas with main summer precipitation and long-time interval rainfalls.