Global Environmental Issues Research Articles

Piezotronic effect and hierarchical Z-scheme heterostructure stimulated photocatalytic H2 evolution integrated with C-N coupling of benzylamine

Photocatalytic hydrogen generation represents a potential approach to address global energy and environmental issues for artificial photosynthesis. Generally, the inevitable use of the holes scavengers leads to increased cost and production of waste. The integration of H2-producing half-reaction with value-added organic molecule oxidation reaction provides a promising strategy to cope with this issue. However, owing to the low separation efficiency of photo-generated charge carriers and sluggish kinetics of the surface reaction, the photocatalytic activity without a co-catalyst is unsatisfying. Herein, the hierarchical and piezoelectric Z-scheme BaTiO3@ZnIn2S4 heterostructure without any co-catalyst were dexterously constructed. The Z-scheme electron transfer paths maintain the strong redox ability of the photo-generated electrons and holes, also offer spatial separation of both charge carriers and the surface redox regions. The well-designed redox regions endow BaTiO3@ZnIn2S4 with the lowest energy barriers of hydrogen production and C-N coupling of benzylamine than that of pure BaTiO3 or ZnIn2S4. Significantly, piezotronic effect can further accelerate the separation and transfer of photo-generated charge carriers in Z-scheme BaTiO3@ZnIn2S4 heterostructure. Thus, by the feat of the multiple advantages of the piezotronic effect and Z-scheme heterostructure, the high photocatalytic activity for the co-production of C-N coupling products (5593 umol g−1) and H2 (8041 umol g−1) was achieved through coupling utilization of mechanical energy and solar energy.

Investigating the toxicity of tropical reservoir sediments using the Allium test

Water pollution is a global environmental issue, and aquatic sediments are important compartments that might act as sinks or sources of contaminants. Once in the environment, inorganic contaminants such as metals can cause cytogenotoxic effects that damage genetic material and harm the aquatic community. Biological assays such as the Allium test can be used to investigate potential cytogenotoxicity of contaminated sediments based on the alterations of cell cycle indexes and chromosomal aberration frequencies. Therefore, we aimed to assess the toxicity of sediments from four Brazilian reservoirs using the Allium test. Sediments were sampled and elutriates were prepared in a simulating sediment resuspension in the water column. The Allium test was applied to the elutriates, and the metals copper, chromium, cadmium, lead, zinc, and iron were quantified. The elutriates derived from reservoir sediments were able to reduce the mitotic and anaphase index, increase the prophase and metaphase index, and boost chromosomal aberrations compared to the negative control. The cytogenotoxic effects observed may be linked to the presence of copper, zinc, and iron. Therefore, our results showed that the Allium test was a sensitive tool for warning the occurrence of genotoxic contaminants in sediment elutriates from four Brazilian reservoirs.

A Study on the Power Line Operation Strategy by the Energy Storage System to Ensure Hosting Capacity of Distribution Feeder with Electrical Vehicle Charging Infrastructure

The introduction of a complex electrical vehicle charging (EVC) infrastructure consisting of an electrical vehicle (EV) charger and renewable energy source (RES) in the distribution system has been required as an important countermeasure for global environmental issues. However, the problems for hosting capacity and power stability of the distribution feeder can be caused by the penetration of lager scaled RES and EVC infrastructure. Further, it is required for the efficient operation method to prevent congestion and to ensure hosting capacity for the distribution feeder due to the increase of variable RES and EVC infrastructure in the distribution systems. In order to solve these problems, it is necessary to develop a technology which is capable of stably introducing an EVC infrastructure without reinforcing the existing distribution system. Therefore, to maintain the existing hosting capacity of distribution feeder and allowable limits, this paper presents a virtual power line (VPL) operation method using Energy Storage System (ESS) based on the power and voltage stabilization control to ensure hosting capacity of the EVS infrastructure. The proposed operation method is determined by optimal power compensation rate (PCR) and voltage compensation rate (VCR). Specifically, ESS for VPL is controlled according to the charging and discharging mode is operated according to the comparison value of the PCR and VCR. From the test results, it is verified that hosting capacity of the distribution system can be maintained using the proposed control method of ESS for VPL operation.

Mapping Global Urban Impervious Surface and Green Space Fractions Using Google Earth Engine

Urban impervious surfaces area (ISA) and green space (GS), two primary components of urban environment, are pivotal in detecting urban environmental quality and addressing global environmental change issues. However, the current global mapping of ISA and GS is not effective enough to accurately delineate in urban areas due to the mosaicked and complex structure. To address the issue, the hierarchical architecture principle and subpixel metric method were applied to map 30 m global urban ISA and GS fractions for the years 2015 and circa 2020. We use random forest algorithms for retrieval of the Normalized Settlement Density Index and Normalized Green Space Index from Landsat images using Google Earth Engine. The correlation coefficients of global urban ISA and GS fractions were all higher than 0.9 for 2015 and circa 2020. Our results show global urban ISA and GS areas in circa 2020 were 31.19 × 104 km2 and 17.16 × 104 km2, respectively. The novel ISA and GS fractions product can show potential applications in assessing the effects of urbanization on climate, ecology, and urban sustainability.

Interpreting Literary Ecologies and Extending Spheres of Concern: A Note on Bachelard’s The Poetics of Space for Eco-Theology

This critical note addresses two key features of eco-theology with regard to future prospect: that literary analysis is an important mode of eco-theological work and that an important function of eco-theology is to expand readers’ spheres of concern to include even the most remote of global environmental issues. Working from Tweed’s contention in Crossing and Dwelling that a central function of religion is the process of making homes, the note emphasizes the home as the primary sphere of concern and the need for eco-theological work to extend the concern naturally associated with the private home to the broadest possible sphere: the whole earth as conceived as human home. As pertaining to literary-analytical resources for this eco-theological endeavor, the note highlights the importance of Gaston Bachelard’s The Poetics of Space. Bachelard’s work offers a compelling exploration of the psychological connection between the most intimate spheres of concern (the private home) and the most extended ones (the broader world). Broader eco-theological engagement with his work will employ resources both for understanding relations between the relative scales of human ecology and for expanding spheres of concern, particularly in extending that concern often reserved for the most intimate ecological sphere to the most expansive.

Potential of Producing Flavonoids Using Cyanobacteria As a Sustainable Chassis.

Numerous plant secondary metabolites have remarkable impacts on both food supplements and pharmaceuticals for human health improvement. However, higher plants can only generate small amounts of these chemicals with specific temporal and spatial arrangements, which are unable to satisfy the expanding market demands. Cyanobacteria can directly utilize CO2, light energy, and inorganic nutrients to synthesize versatile plant-specific photosynthetic intermediates and organic compounds in large-scale photobioreactors with outstanding economic merit. Thus, they have been rapidly developed as a "green" chassis for the synthesis of bioproducts. Flavonoids, chemical compounds based on aromatic amino acids, are considered to be indispensable components in a variety of nutraceutical, pharmaceutical, and cosmetic applications. In contrast to heterotrophic metabolic engineering pioneers, such as yeast and Escherichia coli, information about the biosynthesis flavonoids and their derivatives is less comprehensive than that of their photosynthetic counterparts. Here, we review both benefits and challenges to promote cyanobacterial cell factories for flavonoid biosynthesis. With increasing concerns about global environmental issues and food security, we are confident that energy self-supporting cyanobacteria will attract increasing attention for the generation of different kinds of bioproducts. We hope that the work presented here will serve as an index and encourage more scientists to join in the relevant research area.

Light pollution as a factor in breast and prostate cancer

Light pollution is a global environmental issue that affects photosensitive organisms. For instance, several researchers have recognized melatonin suppression in humans as a direct cause of long-term exposure to high artificial light levels at night. Others have identified low melatonin levels as a risk factor for a higher prevalence of hormone-sensitive cancer. This paper analyzes the association between light pollution, estimated as the emission analysis of satellite worldwide nighttime light collections from 1999 to 2012, and 25,025 breast and 16,119 prostate cancer events from 2003 to 2012. Both types of cancer increased during the study period, but light pollution increased in urban and peri-urban areas and decreased in rural areas. Cumulative light pollution during 5 years showed a positive association with breast cancer but not with prostate cancer. The association between light pollution and breast cancer persisted when adjusted to age-standardized rates with a mean increase of 10.9 events per 100,000 population-year (95% confidence interval 7.0 to 14.8). We conclude that exposure to elevated light pollution levels could be a risk factor for breast cancer in Slovakia. This work can interest researchers who study relationships between atmospheric pollutants and the growing cancer epidemic. The results and the methodology can be extrapolated to any country in the world if data is available.

Eelgrass (Zostera marina) and its epiphytic bacteria facilitate the sinking of microplastics in the seawater

Marine microplastics have received considerable attention as a global environmental issue. However, despite the constant accumulation of microplastics in the ocean, their transport processes and mechanisms remain poorly understood. This study investigated microplastics in the sediments of seagrass meadows and nearby regions without seagrass along the Shandong coast and found that the sediment in the seagrass meadows was a sink for microplastics. Subsequently, we evaluated the influence of eelgrass (Zostera marina), a common coastal seagrass, on the sedimentation of suspended polystyrene microplastics. The results showed that 0.5, 1.0, and 2.0 g/L eelgrass leaves decreased the abundance of microplastics in seawater in a dose-dependent manner over a period of 3–48 h under shaking conditions at 120 rpm at 22 °C. After 48 h of shaking, microplastic abundances in the 0.5, 1.0, and 2.0 g/L eelgrass groups significantly decreased by 46.9%, 53.1%, and 88.4%, respectively. Microplastics can adhere to eelgrass leaves and form biofilms, which promoted the formation of white floc that traps the suspended microplastics, causing them to sink. Furthermore, two epiphytic bacteria (Vibrio and Exiguobacterium) isolated from the eelgrass leaves decreased the abundances of suspended microplastics by 95.7% and 94.5%, respectively, in 48 h by accelerating the formation of biofilms on the microplastics. Therefore, eelgrass and its epiphytic bacteria facilitated the sinking of microplastics and increased the accumulation of microplastics in the sediments of seagrass meadows in coastal regions.

Spherical In2S3 anchored on g-C3N4 nanosheets for efficient elemental mercury removal in the wide temperature range

Mercury emission from coal-fired power plants has posed a great threat to the environment and human, and reducing and controlling mercury emissions has become a global environmental issue. In this work, the In2S3/g-C3N4 adsorbent was prepared by simple hydrothermal method to achieve efficient removal of Hg0 from coal-fired flue gas. When the loading value of In2S3 was 40 %, the effect of removing Hg0 by as-synthesized IC-40 was the best. IC-40 showed excellent Hg0 adsorption performance in a temperature range of 80–240 °C. Under the condition of 120 °C and N2 atmosphere, the Hg0 adsorption capacity of the synthesized IC-40 reached 14.78 mg/g. The study on the impacts of flue gas components demonstrate that IC-40 has good resistance to nitric oxide, and has a slight inhibitory effect by SO2 and water vapor. According to the results of XPS and Hg-TPD, the formed main mercury compound is extremely stable HgS. In addition, DFT was conducted to calculate the adsorption energy of Hg0 on In2S3 (110) surface, which further illustrated the sulfur site served as stable adsorption site to convert Hg0 into HgS. From the above analysis, IC-40 as an efficient and scientific adsorbent to remove Hg0 from coal-fired power plants is a promising technical method.

Developing sustainable measures to restore fly‐ash contaminated lands: Current challenges and future prospects

AbstractLand degradation is one of the major global environmental issues that need serious attention. The land itself is a complex system regulating myriads of processes. Any perturbation in these processes would undoubtedly lead to the stimulation of land degradation. Among these, fly‐ash (FA) dumping is one of the usual practices, which has been adopted to overcome land‐use disruption and other health hazards. However, this practice has become a driving factor for FA‐induced land degradation. Therefore, in purview to tackle this issue, the present article aimed to identify and suggest sustainable practices to restore and manage FA‐contaminated sites. As a preliminarily it deals with the systematic exploration and identification of FA‐based and associated contaminated lands via geospatial technology with a brief focus on assessing its different contaminant profiles in the FA and soil systems. Further, this moreover, the article emphasizes the need to identify identifying the potential local plant species in the FA‐contaminated regions that can meet the local people's demands. Following this we suggest appropriate sustainable approaches to expedite the restoration of FA‐contaminated lands and highlight the critical bottlenecks during ground implementation. Our article aimed to unravel ways to address the aforementioned bottlenecks to develop an efficient restoration enterprise during the UN Decade on Ecosystem Restoration (2021–2030).

Towards global public trust doctrines: an analysis of the transnationalisation of state stewardship duties

ABSTRACT Public trust doctrines (PTDs) provide that natural resources, like air, trees and water, are common, shared property among citizens and therefore nation states should perpetually steward them. This article contributes a new conceptual framework for analysing and applying PTDs against global environmental issues. First, based on a review and synthesis of public trust scholarship, laws and judgments, an overview of PTDs across sub-national, national and international levels is provided. Second, three internationalisation processes of PTDs are defined and analysed, including states: spreading PTDs into other national and international legal systems; applying related international principles; and ratifying treaties with public trust regimes. Third, three transnationalisation processes of PTDs are defined and analysed, including states: stewarding natural resources beyond their territories; stewarding natural resources for all Earth's inhabitants; and jointly stewarding natural resources with other states and organisations. This article concludes that global PTDs are emerging from recent legislation, litigation and treaties.

The contributions of the roots, stems, and leaves of three grass species to water erosion reduction on spoil heaps

Soil erosion on spoil heaps is one of the global environmental issues, where grass recovery is often implemented. However, information regarding how the erosion processes and control efficiency on spoil heaps differ as functions of grass types and components is lacking. In this study, a series of artificial rainfalls (48, 72, and 108 mm h−1) were conducted on eight plots (each one was replicated) that were established on steep spoil heaps and treated with three different grass types (Artemisia gmelinii (AG), Medicago sativa (MS), and Cynodon dactylon (CD)), with measurements of the runoff generation, sediment yield, and runoff velocity. Bare plot (BS) was set up as a control. Three scenarios regarding erosion efficiencies that by intact grass (IG), a combination of grass stems and roots (NL), and only grass root (OR), were considered. The results showed: 1) grass recovery can significantly reduce soil loss rate (SLR) on spoil heaps up to 99%, and there was no significant difference in erosion reduction efficiency between grasses with a taproot (AG: 93%) and fibrous root (MS: 92%; CD: 89%) systems under the IG treatments (P > 0.05); 2) The effect of the different grass treatments on SLR reduction depended on the rainfall intensity. The contribution rate of roots to SLR reduction was 68%–90% at a rainfall intensity of 48 mm h−1, while the stem and leaf contribution rates were 39%–156% at intensities of 72 and 108 mm h−1, respectively. While incomplete grass even increased the SLR, especially in the OR treatment, where the contribution rate of root to SLR reduction was −2%– −68%. 3) The IG treatment reduced soil erodibility (Kr) by 81.43%–83.80%, while the Kr values of the OR treatment were 1.51–3.53 times greater, as compared to the BS plots. In most cases, the critical shear stress (τc) on the grass plots was 1.09–2.14 times greater than those in the BS plots. These results would guide the selection of grass species for controlling spoil heaps erosion, also highlight the necessity of maintaining grass to maximize its control efficiency.

Evaluating Marine Debris Trends and the Potential of Incineration in the Context of the COVID-19 Pandemic in Southern Bali, Indonesia

Highlight Research:The potential calorific value of marine debris obtained from calculating the total waste is 12.05 MJ/kg, which still falls within the incinerator application's standard criteria. AbstractMarine debris, a global environmental issue today, is a major threat to Bali’s seas which are famous for its natural beauty and aggravated by the spread of COVID-19 pandemic. This study aimed to determine the characteristics of marine debris in Bali Island, especially in the southern region and to analyze the feasibility of incineration as one of the waste treatment processes. This research was conducted by utilizing secondary data and literature reviews from related previous studies. Water content and caloric value were measured directly using the ASTM E 790-15 and ASTM D 5865-11a standards. Marine debris generation from 2013 to 2019 tends to decrease from 1.22 kg/km.day to 0.46 kg/km.day. Organic waste (59.4%) comprised the largest marine debris followed by plastic waste (13.4%) and diapers (11.9%). Thermal technology such as incineration can be introduced to treat marine debris. The standard application of incinerator technology is moisture content and caloric value. The water content of marine debris is reportedly 54.56%, therefore, further preliminary processing is needed, especially for waste with high moisture content, such as diapers and organic waste. The potential calorific value of marine debris during the COVID-19 pandemic obtained from calculating the total waste was 12.05 MJ/kg which still did not meet the incinerator application's standard criteria.

Nuclear power in Russia’s national projects

Population supports the need for switching to green power, which is most often understood to mean the use of solar and wind energy. It would be however a mistake to think that solar and wind power plants will solve in full the problem of uninterrupted power supply for all sectors of economy due to the instability of generation modes and the scale of such energy production. Experts suggest that the only possible way to address global energy and environmental issues is further evolution of nuclear power. Nuclear power is not listed explicitly as a national priority project but it is a component of the Science national project and is expected to contribute to the implementation of the Ecology, Education, and International Cooperation and Export projects. In the context of the Ecology project, nuclear power is capable to play a key role in preventing environmental contamination. In the framework of the International Cooperation and Export project, it is possible to export high-technology fast neutron reactors. The experience of interaction with the interested public, and the developed and implemented occupational training programs will provide for the shaping of radiological literacy among young people as part of the Education project.

Acid rain reduces soil CO2 emission and promotes soil organic carbon accumulation in association with decreasing the biomass and biological activity of ecosystems: A meta-analysis

Acid rain, as one of the global environmental issues, alters the biogeochemistry of terrestrial ecosystems. However, the responses of soil greenhouse gases (GHGs) emissions to acid rain remain unclear, thus creating large uncertainties in the prediction of global climate change. Here, we conducted a meta-analysis based on existing 42 studies to assess the influences of acid rain on soil GHGs emissions. Results showed that acid rain significantly decreased soil CO2 emission by 11.7%, but marginally increased soil N2O emission by 11.7%. In addition, acid rain significantly decreased soil pH, dissolved organic carbon (C), microbial biomass C, nitrate nitrogen (N), hydrolysable N and total phosphorus, while increased soil organic C, ammonium N and C/N ratio. Moreover, acid rain significantly decreased the activity of soil urease, sucrase and invertase. Acid rain significantly decreased soil bacterial and gram-negative bacterial biomass, while increased the microbial biomass of gram-positive bacteria, fungi and actinomycete, and the ratios of fungi/bacteria and gram-positive/gram-negative bacteria. Furthermore, acid rain significantly decreased the aboveground biomass and fine root biomass of vegetation. The effect size of soil CO2 emission had significantly positive relationships with that of soil pH, microbial biomass C, urease activity, and fine root biomass, while it negatively related with that of soil organic C and C/N ratio. These findings suggest that acid rain reduces soil CO2 emission and promotes soil organic C accumulation.

3D Tree Reconstruction in Support of Urban Microclimate Simulation: A Comprehensive Literature Review

The negative climate change induced by rapid urbanization has become a global environmental issue. Numerous studies have been devoted to microclimate regulation functions performed by urban vegetation. Digital city information modeling provides a powerful tool for various simulations and data analytics for the sustainable development of urban areas. However, the method reconstructing urban trees is still in its early stage compared to the relatively mature building modeling. Most prior studies on tree reconstruction focused on retrieving geometric features, while other factors related to urban microclimate simulation were rarely addressed. This paper presents a comprehensive literature review and in-depth analysis covering two distinct research directions in relation to urban microclimate simulation. The first one is set on the identification of key factors related to trees’ impact on urban microclimate. The second one is dedicated to approaches for three-dimensional (3D) tree reconstruction. Based on the findings, the paper identifies information including trees’ geometric, physiological characteristics and relation to the surroundings required for 3D tree reconstruction in the context of urban microclimate simulation, and further assesses the potential of the 3D tree reconstruction approaches to accommodate these pieces of information. An appropriate 3D tree reconstruction approach, which allows for the supply of the required information for urban microclimate simulation, is recommended.

Tailoring multifunctional gel for sensitive naked-eye and fluorescence dual-mode detection and effective adsorption of cadmium(Ⅱ) and lead(Ⅱ) ions in water

Water contamination caused by toxic cadmium (Cd2+) and lead (Pb2+) has become a global environmental issue, making it imperative to develop versatile functional materials for their monitoring and remediation. However, developing a versatile platform for the simultaneous sensitive multiple signal detection and effective removal of Cd2+ and Pb2+ remains a formidable challenge. Herein, a multifunctional gel for sensitive detection and effective adsorption of Cd2+ and Pb2+ is facilely constructed by integrating glycidyl methacrylate functionalized fluorescent graphene quantum dots and N, N'-methylenebisacrylamide co-crosslinked poly(thioctic acid) with physical crosslinked fluorescent gelatin. Interestingly, the gel shows cyan to chartreuse/violet fluorescence color change and fluorescent turn-on/turn-off switch after adsorbing Cd2+/Pb2+, thus for the first time simultaneous sensitive naked-eye and fluorescence dual-mode detection of Cd2+ and Pb2+ are achieved in a broad liner range (0.02–0.24 μmol). Meanwhile, the gel can effectively absorb Cd2+ and Pb2+ in water with maximum adsorption capacities of 194.553 and 259.067 mg g−1, respectively, surpassing previously reported adsorbents. Additionally, the gel exhibits excellent self-healing capability, reprocessability, biodegradability and biocompatibility, which can prolong its service life and prevent secondary contamination in practical applications. This study not only develops a versatile platform for the simultaneous sensitive detection and effective removal of Cd2+ and Pb2+, but also provides an innovative design strategy for inspiring future research to fabricate multifunctional materials for monitoring and decontamination heavy metal polluted water.

Mycotoxin-mixture assessment in mother-infant pairs in Nigeria: From mothers' meal to infants’ urine

Exposure to food and environmental contaminants is a global environmental health issue. In this study, innovative LC-MS/MS approaches were applied to investigate mycotoxin co-exposure in mother-infant pairs (n = 23) by analyzing matched plate-ready food, breast milk and urine samples of mothers and their exclusively breastfed infants. The study revealed frequent co-occurrence of two to five mycotoxins. Regulated (e.g. aflatoxins, deoxynivalenol and ochratoxin A) and emerging mycotoxins (e.g. alternariol monomethyl ether and beauvericin) were frequently detected (3 %–89 % and 45 %–100 %), in at least one specimen. In addition, a moderate association of ochratoxin A in milk to urine of mothers (r = 0.47; p = 0.003) and infants (r = 0.52; p = 0.019) but no other significant correlations were found. Average concentration levels in food mostly did not exceed European maximum residue limits, and intake estimates demonstrated exposure below tolerable daily intake values. Infants were exposed to significantly lower toxin levels compared to their mothers, indicating the protective effect of breastfeeding. However, the transfer into milk and urine and the resulting chronic low-dose exposure warrant further monitoring. In the future, occurrence of mycotoxin-mixtures, and their combined toxicological effects need to be comprehensively considered and implemented in risk management strategies. These should aim to minimize early-life exposure in critical developmental stages.

In situ removal of cadmium by short-distance migration under the action of a low-voltage electric field and granular activated carbon

Cd pollution in soil is a global environmental issue of great concern. The secondary release and low removal rate of Cd are obstacles to the use of adsorption techniques. To develop a sustainable and effective remediation technique, low-voltage direct current (DC) and granular activated carbon (GAC) were applied for in situ Cd removal. The results showed that a low-voltage gradient was more favourable than a high-voltage gradient for Cd removal. A voltage gradient of 0.2 V cm−1 acted as a driving force for Cd migration while limiting the side effects caused by DC. As an auxiliary enhancement measure, polarity exchange was effective in maintaining uniform distributions of soil moisture and temperature as well as a stable pH while improving Cd removal by weakening inhibition caused by OH− generated at the cathodes. The average removal rates of total and bioavailable Cd were 61.05% and 76.96%, respectively. The potential mobility of Cd in soil was assessed by the mobility factor (MF). The MF was lowered from 42.66% to 8.96%, indicating that the risks of Cd mobility were reduced to low levels. The energy consumption and utilization efficiency of the method were 5.65 KWh m−3 and 11.25, respectively. The energy utilization efficiency was significantly higher than the efficiencies of other methods that use DC to improve Cd removal. The results suggested that the in situ removal of Cd by low-voltage DC and GAC was efficient and avoided the secondary release of Cd.

Effects of garbage salvaging and suspended crossbar on microplastic pollution along a typical urban river.

Microplastic pollution has been considered as a global environmental issue that potentially threatens human health. However, research about microplastic pollution in urban rivers is still insufficient. This study analyzed the abundance and distribution of microplastics in surface water of the Nanfei River in Hefei, China. Microplastic concentrations ranged from 0.8 to 27 items/L along the studied river. The small size (50-333μm) (47.58-84.89%) and white (55.65-88.89%) were predominant among all samples, except that collected from the source reach. Pellet was a typical and abundant microplastic type and accounted for 60.30%. PE and PP were the major polymers, occupying 55.24% and 22.86%, respectively. The results showed that traditional environmental management practices including salvaging surface garbage regularly and setting wooden suspended crossbars at tributary confluences could significantly mitigate the pollution degree of microplastics. The polymer risk index was calculated to describe the potential risk of microplastics, and the pollution level was still at high risk under various management practices. This study provides a valuable finding for future research on microplastics in urban city rivers, which may improve the knowledge that how to control and prevent microplastic pollution.