River Pollution Research Articles

Distribution and response of electroactive microorganisms to freshwater river pollution

Electroactive microorganisms (EAMs) play a vital role in biogeochemical cycles by facilitating extracellular electron transfer. They demonstrate remarkable adaptability to river sediments that are characterized by pollution and poor water quality, significantly contributing to the sustainability of river ecosystems. However, the distribution and diversity of EAMs remain poorly understood. In this study, 16S rRNA gene high-throughput sequencing and real-time fluorescence quantitative PCR were used to assess EAMs in 160 samples collected from eight rivers within the Pearl River Delta of Southern China. The results indicated that specialized EAMs communities in polluted sediments exhibited variations in response to water quality and sediment depth. Compared to clean sediment, polluted sediments showed a 4.5% increase in the relative abundances of EAMs communities (59 genera), with 45- and 17-times higher abundances of Geobacter and cable bacteria. Additionally, the abundance of cable bacteria decreased with increasing sediment depth in polluted sediments, while the abundance of L. varians GY32 exhibited an opposite trend. Finally, the abundances of Geobacter, cable bacteria, and L. varians GY32 were positively correlated with the abundance of filamentous microorganisms (FMs) across all samples, with stronger interactions in polluted sediments. These findings suggest that EAMs demonstrate heightened sensitivity to polluted environments, particularly at the genus (species) level, and exhibit strong adaptability to conditions characterized by high levels of acid volatile sulfide, low dissolved oxygen, and elevated nitrate nitrogen. Therefore, environmental factors could be manipulated to optimize the growth and efficiency of EAMs for environmental engineering and natural restoration applications.

Biophysics indicators as the sustainable strategy for river pollution control (case study in Jangkok River, Mataram City, West Nusa Tenggara)

Background: Sungai Jangkok is one of those considered heavily polluted in NTB. The Biochemical Oxygen Demand (BOD) value has exceeded the standard for Class II water quality, and according to the Family Biotic Index (FBI) value, the river falls under the category of heavy organic pollution. The research objective is to realize sustainable management of the Jangkok Watershed in accordance with its river functions by implementing pollution control strategies. Methods: Data collection was conducted using questionnaires and interviews with the public and stakeholders (government and NGOs). Water quality data was obtained from DLHK NTB and DLH Mataram City, and sampling was carried out using the composite sample technique. The methods employed were STORET, QUAL2Kw, logistic regression, and SWOT. Findings: The research findings indicate that, in general, the Jangkok River in Mataram City falls into the heavily polluted category from 2015 to 2022, with an average STORET score of -79.25. Moreover, the pollution loads of BOD, COD, and TSS entering the river have exceeded the pollution carrying capacity. The condition is influenced by several factors, including the less favorable perception of pollution status (67%) and the usefulness of the river (59%) by the community. Additionally, the persistent behavior of littering and/or defecating in the river (23%), inadequate preventive practices (59%), insufficient wastewater disposal facilities (40%), and improper waste management (58%) are contributing factors. Moreover, the existence of houses backing up to the river (59%) also plays a role in the current condition. Some of the causes are the lack of synergy across administrative regions between stakeholders, the absence of law enforcement for the community, dependency on government budget for work programs, and the lack of incentives. Conclusion: The conclusion of this research suggests that the most effective strategy for taking is to develop a program for reducing pollutant loads that is integrated across districts and cities, integrated across agencies with various levels of authority, integrated with the community, and in accordance with the river's actual conditions and the socioeconomic community. Novelty/Originality of this Study: This study provides a novel approach by integrating quantitative water quality modeling (QUAL2Kw) with community behavior analysis to develop a sustainable and comprehensive strategy for controlling river pollution in the Jangkok watershed, Mataram City.

Global risk assessment of river pollution stress based on nighttime light remote sensing data

Rivers play a crucial role in the development of human civilization, and river pollution is a significant environmental issue that accompanies with intensified human activity. However, the evaluation of river pollution at a global scale is difficult because of the limitations of long-term pollution-related datasets. As human activities are the main factor causing river pollution, nighttime light (NTL) remote sensing data can be used as an alternative indicator of the risk of river pollution stress(RPS), which is closely related to human activities and refers to the amount of pollutants within the confluence range of river reaches. In this study, we propose a river pollution pressure index (PI) to indicate risk of RPS by considering the accumulation effect of water flow. Then we calculated PI of over 0.67 million reaches global with annual total flow >100 million m3/s from 2000 to 2022, which was validated using water quality data of >2000 river sections in China. The results show that, from 2000 to 2022, the spatial variations of the risk of RPS are uneven, with a migration trend from west to east. The risk of RPS continues to increase globally, especially rapidly after 2010. Central Asia, Southeast Asia, East Asia, and eastern China are the regions with the fastest growth rates. In most developed countries, developing countries, and underdeveloped countries, the risk of RPS is high and increasing slowly, moderate and increasing rapidly, and low and increasing slowly, respectively. However, in some special cases, such as Japan, the risk of RPS continues to decrease. These spatiotemporal variations of the risk of RPS correlate with global events, such as quantitative easing of global economy after 2008, China's “Belt and Road Initiative”, and COVID-19. This study demonstrates that NTL data can be applied to evaluate the global risk of RPS.

Pollution loads in the middle-lower Yangtze river by coupling water quality models with machine learning

Pollution control and environmental protection of the Yangtze River have received major attention in China. However, modeling the river's pollution load remains challenging due to limited monitoring and unclear spatiotemporal distribution of pollution sources. Specifically, anthropogenic activities’ contribution to the pollution have been underestimated in previous research. Here, we coupled a hydrodynamic-based water quality (HWQ) model with a machine learning (ML) model, namely attention-based Gated Recurrent Unit, to decipher the daily pollution loads (i.e., chemical oxygen demand, COD; total phosphorus, TP) and their sources in the Middle-Lower Yangtze River from 2014 to 2018. The coupled HWQ-ML model outperformed the standalone ML model with KGE values ranging 0.77–0.91 for COD and 0.47–0.64 for TP, while also reducing parameter uncertainty. When examining the relative contributions at the Middle Yangtze River Hankou cross-section, we observed that the main stream and tributaries, lateral anthropogenic discharges, and parameter uncertainty contributed 15, 66, and 19% to COD, and 58, 35, and 7% to TP, respectively. For the Lower Yangtze River Datong cross-section, the contributions were 6, 69, and 25% for COD and 41, 42, and 17% for TP. According to the attention weights of the coupled model, the primary drivers of lateral anthropogenic pollution sources, in descending order of importance, were temperature, date, and precipitation, reflecting seasonal pollution discharge, industrial effluent, and first flush effect and combined sewer overflows, respectively. This study emphasizes the synergy between physical modeling and machine learning, offering new insights into pollution load dynamics in the Yangtze River.

Balancing river water pollution and agricultural development: A tradeoff threshold approach

Balancing environmental protection and social-economic development in agricultural land use management is a dilemma for decision-makers. Based on the modelling of the impacts of land use changes on river water pollution by SWAT model, the tradeoff between tea plantation expansion and river water quality was detected. SWAT model performs well in simulating the non-point source (NPS) pollution in agricultural watershed. The results showed that the tea plantation area expanded dramatically from 44 km2 in 2000 to 169 km2 in 2020 at the high cost of forest land. Consequently, the mean contents of NO3−-N and TN have significantly increased by 100% and 91% respectively in the past 20 years. And the NO3−-N in river water accounted for over 80% of TN in the tea plantation area. The NO3−-N and TN concentrations were positively related with the proportions of tea plantation area (Tea%) at different periods. The high pollution levels of NO3−-N and TN are priority control targets for river water quality management. The results indicated that the proportion of tea plantation thresholds lead to abrupt changes in river water quality. When the Tea% exceeded 3.0% in 2000, the probability of N pollution increased sharply. Whereas in 2020, it is suggested that the Tea% should not exceeds 18% to avoid sudden deterioration of water quality. The critical interval value of the Tea% for sudden change in N pollution showed an obvious increase tendency. The accelerating of nutrient pollution in rivers reduced the sensitivity of water quality to tea plantation expansion. Our results can provide new insights and empirical evidence for balancing the tradeoff between agricultural development and river water quality protection by demonstrating the carrying capacity threshold of river water environment for the expansion tea plantation.

Numerical simulation of hydraulic characteristics and pollutant transport in the channels with different ice coverages

ABSTRACT In winter, rivers at high latitudes often freeze and an ice cover emerges at the free surface of the river. According to the coverage degree of the ice cover, rivers can be divided into free-flowing, partially frozen, and completely frozen. The presence of ice cover can greatly alter the hydraulic conditions of rivers, complicating the transport of pollutants in river channels. The distribution of pollutants in rivers with different ice coverages was simulated using the Detached Eddy Simulation (DES) model in this paper. The velocity distribution, the pollutant diffusion coefficient distribution, the turbulent kinetic energy distribution, and the vortex distribution with different ice coverages were analyzed. The velocity in the ice cover zone is at a lower rate than in the open flow zone. With the increase of the ice coverage, the turbulent kinetic energy of the ice cover area in partially frozen conditions gradually increases, which makes the water flow turbulence increase. The diffusion coefficient of pollutants in the ice cover area is greater than that in the open flow area, so pollutants disperse more quickly in the ice cover area. The turbulence energy and the diffusion coefficient have similar distribution characteristics beneath the ice cover. The presence of the ice cover promotes the movement of the vortex from the open flow area to the ice cover area, which may be the reason for the larger turbulence energy and the diffusion coefficient. The simulation results can provide a reference for ice disasters and water quality remediation.

The Impact of Sewage Water Overflow (SWO): An Analysis of Zandspruit River in Cosmo City, Johannesburg, South Africa

Cosmo City, situated in Johannesburg, Gauteng, has been experiencing sewage water overflows (SWO) for several years, and this raises concerns about the water quality of Zandspruit River. The study aimed to investigate the impacts of SWO on the Zandspruit River, and the perceptions of the community towards SWO. Water samples were collected from three sampling sites of Zandspruit River. Some water quality parameters were measured in the field using a multi-parameter water quality meter while other parameters were analyzed at a SANAS accredited laboratory. Results were compared with South African water quality guidelines and most water quality parameters were within permissible set standards. However, COD, E. coli and turbidity were above permissible set standards which indicates a highly polluted river. Furthermore, we assessed perceptions of the Cosmo City community towards SWO through questionnaires. The community ascribed the main causes of SWOs to population growth, blocked, and broken sewers. This study revealed that SWO around Cosmo City has a negative impact on the quality of river water and poses health risks. The combined evidence from both the experimental analysis and the community perception survey underscores the urgent need for effective management strategies to address the negative environmental and human health implications of SWO in the Zandspruit River. By integrating these findings and considering the broader implications of pollution on both the ecosystem and community well-being, policymakers and stakeholders can work towards implementing sustainable solutions to mitigate the risks associated with sewage water overflows.

Riverine seasonal rainfall event tracing of organic pollution sources using fluorescence fingerprint difference spectrum

Elucidating the dynamics of dissolved organic matter (DOM) transport and transformation under seasonal rainfall events is essential for the conservation of riverine ecosystems, for mitigating the effects of climate change, and for crafting informed water management strategies. Therefore, this study aimed to investigate the evolutionary characteristics of organic pollution sources during consecutive rainfall events in early spring and to quantify their relative contributions to the process of surface water pollution. The results showed seasonal rainfall induces water quality exceedances in rivers due to the combined impacts of terrestrial inputs and endogenous releases. Humic acid (HA) (region V) and fulvic acid (FA) (region III) emerged as the predominant organic matter in the water column, with their fluorescence intensity altering as rainwater flushed the riverbed. Sources of pollution include agricultural and urban domestic sources (AS + DS) (72.29 %), industrial and urban domestic and microbial sources (IS + DS + MS) (37.71 %), and agricultural and industrial sources (AS + IS) (63.32 %), indicating that agricultural surface pollution discharges contribute significantly. The gas–chromatography–mass spectrometry (GC–MS) further confirmed that exogenous inputs were predominantly comprised of particulate pollutants. This study underscores the efficacy of fluorescence difference spectrometry in delineating the migration and transformation of river pollution sources during seasonal rainfall and facilitating the implementation of targeted management strategies for river ecosystems.

Potential of Vermifiltration Technique to Reduce Chemical Oxygen Demand, Biological Oxygen Demand, and Total Suspended Solid of Farm Dairy Effluent in Developing Countries: Case of Indonesian Farm Dairy Industry

Farm dairy effluent (FDE) contains high level of Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), and Total Suspended Solids (TSS) which caused river and groundwater pollution. To reduce those parameters, vermifiltration technique was utilized for dairy effluent treatment. It also could reduce greenhouse gasses (GHG) emissions, removing organic and excessive nutrients without odor and recovering manure nutrients in the treated dairy effluent and vermicompost. The objective of this study is to evaluate the potential of Vermifiltration in reducing COD, BOD and TSS of the FDE. Samples of wastewater were collected from dairy farm industry from 3,542 of total cow populations located in Bandung regency, Indonesia. The sample characteristics of COD, BOD, TSS, pH, NH3-N, organic carbon, and macro nutrients (total N, P2O5, and K2O) were measured before and after vermifiltration treatment. Vermifiltration treatment will produce two types of products i.e.: tea water and vermicompost. The result showed that Vermifilter removed the COD, BOD, and TSS of 93%, 95%, and 93% respectively. The organic carbon NH3-N, and total macro nutrients generally decreased after treated by Vermifilter (2.01 to 0.0001% of organic carbon, 718 to 3.75 mg L-1 of NH3-N, 0.2 to 0.02% of total N, 0.19 to 004% P2O5, 0.57 to 0.18% of K2O); however, the pH was not significantly changing (from 8.13 to become 8.05). Vermicompost produced by vermifiltration beds by earthworms consumes sewage solids and excreting them in the vermicast which produces high macronutrients (2.4% of total N, 5.5% of P2O5, and 0.75% of K2O), and organic carbon (15.6%), hence beneficial for soil fertilizer. Vermifilter effectively degrades the organic matter in the dairy effluent. Derivatives produced by the Vermifiltration process, namely tea water and Vermicompost, can be used as substitutes for irrigation materials and organic fertilizers on agricultural land, and act as soil conditioners to improve soil properties.

Risks and benefits associated with the consumption of three species of fish native to the Brazilian Amazon

In the Brazilian Amazon, fish is part of the diet and culture of the native population. With industrialization and the pollution of rivers, the number of cases of people contaminated by toxic pollutants present in fish has grown. Therefore, the objective of this study was to analyze three species of fish from the Amazon, the curimatã, pescada-gó, and piramutaba, to investigate the risks and benefits associated with the consumption of their muscles and livers in different seasonal periods. The amino acid and fatty acid profiles were investigated by liquid and gas chromatography, respectively. The essential elements (Cu, Fe, Mg, Na, and Zn) were quantified by flame atomic emission spectrometry, and the contaminants lead (Pb) and mercury (Hg) by flame atomic emission spectrometry and graphite furnace. Significant amounts of unsaturated fatty acids were found in muscle and liver. The polyunsaturated acids were more present in the pescada-gó and the monounsaturated in the curimatã. Contaminants (Pb and Hg) were found at levels higher than the limit allowed by Brazilian legislation. The curimatã species contributed more than 131.79% of the Hg, exceeding the tolerable weekly limit, and is considered unfit for consumption. The study demonstrated that constant biomonitoring of species traded in the region is necessary to ensure food security.

“URBAN REHABILITATION IN RUSSIA BROOKS NO DELAY”: STATE AND SOCIETY IN THE FIGHT AGAINST RIVERS POLLUTION AT THE END OF THE 19th — EARLY 20th CENTURIES

At the turn of the 19th and20th centuries, the growth of urban population and development of urban infrastructure were accompanied by the emergence of environmental problems, including the increase of river pollution, which might cause water supply diffi culties. The central and local authorities, as well as representatives of various public, scientific, professional organizations and business circles, were involved in solving these problems. The order of their interaction could be diff erent, but these joint projects made it possible to achieve the best results in combating river pollution caused by industrial and domestic waste, to determine priorities in the system of water protection and to improve the supply of potable water to the population. Thanks to the activities of such organizations as the Society for Assistance to the Improvement and Development of Manufacturing Industry, Russian Water Supply Congresses, sanitary stations, and the Provisional Committee for the Development of Measures to Protect the Water Bodies of the Moscow Industrial District from Pollution, a rather extensive set of measures was carried out to study the properties, nature, and degree of water pollution in the rivers that served as sources of water supply for city dwellers, and the most eff ective methods of water purifi cation were determined in experiments. Practical recommendations were developed on the use of the most eff ective and cost-efficient methods and facilities for industrial wastewater treatment. The best domestic specialists were involved in solving the identified problems, who utilized international and Russian experience. The lack of sufficient funding for water protection activities resulted in some initiatives not being or being only partially implemented. In addition, a number of practical measures which had been planned in this area had to be postponed because of the outbreak of World War I in 1914

Exploring the long-term impact of a cadmium pollution accident on microbial communities in river ecosystems

The large leakage accidents of heavy metals from industrial facilities pose a serious environmental problem; however, not enough studies have been conducted to assess the long-term ecological risk associated with such accidents. This study evaluated changes in the bacterial communities within river sediment and identified the key functional microorganisms responding to the 2012 cadmium contamination incident in the Long River, Guangxi Province, China. Results revealed that after a prolonged period of pollution accidents, cadmium pollution still had a discernible effect on the bacterial communities of the river sediment. In comparison to the control site (S1), the bacterial α-diversity in sediments from the accident area (S3) and its downstream (S5) showed a significant increase following the incident. In the control site, Burkholderiaceae was dominant, while in S3 and S5, Pedosphaeraceae, Nitrosomonadaceae, Nitrospiraceae and Geobacteraceae were significantly increased. Sulfur bacteria were found to be more responsive to this cadmium contamination than other bacteria. At site S3, the abundances of Sulfuricurvum, Sulfurifustis, Thioalkalispira, Desulfobacteraceae and Desulfarculaceae were hundreds of times higher than at site S1, indicating an intensification of sulfur cycling processes. The functional prediction implied that cadmium pollution may promote methane oxidation coupled with sulfate reduction reactions and altered the processes of nitrification and denitrification. Environmental factors influencing the microbial community included the levels of metals (cadmium, arsenic, iron) in sediment, as well as other sediment characteristics like temperature and electrical conductivity. These findings contribute to our understanding of the long-term ecological consequences of environmental pollution in river ecosystems.Graphical abstract

Transforming stench to scent – the case of Phool.Co.

Learning outcomes After completion of the case study, students will be able to decipher key concepts underpinning sustainable entrepreneurship and its application in the recognition and exploitation of sustainable business opportunities, decipher the application of circular economy business models, understand the pivots to achieve the billion-dollar valuation and analyse the strategies for value creation during the pivoting journey of a startup. Case overview/synopsis The case study traces the journey of Phool.Co, a sustainable biomaterial startup based in a Tier II city of Kanpur located in the state of Uttar Pradesh, India, by Ankit Agarwal in 2017. Agarwal started with the vision of providing solution to the effects of water pollution and environmental damage. Ganga is not just a river, rather it is the symbol of cultural and religious faith in India. Although the river Ganga is considered a deity in India, it is one of the most polluted rivers. Every year 8,000,000 metric tonnes of waste flowers are dumped into the sacred river to pollute it further. The pollution poses grave dangers to the health and livelihood of millions of Indians. Phool.Co is a sustainable enterprise that has pioneered flower cycling technology. The dumped flowers are recycled to produce organic incense sticks, Florafoam, and “Fleather – the organic alternative to leather”. The case study traces the genesis of Phool.Co and its approach towards sustainability in the context of the circular economy. The case study primarily explores the pivot points for a startup to enter the unicorn club in the present context. To achieve the desired valuation, Agarwal must decide to rethink its business model. Will franchise model work for Phool.Co? Should Agarwal scale up with commercialization of Florafoam to capitalize the opportunity in packaging industry? Vegan leather is a nascent market and how will the consumers respond to Fleather is a pertinent question. The case study attempts to explore the challenges encountered in augmenting the valuation of sustainable enterprises. Complexity academic level This case study is suitable for graduate and postgraduate students enrolled in courses related to entrepreneurship, innovation and sustainability. The case study is of intermediate-level difficulty. There are no specific prerequisites to understand the case. Supplementary materials Teaching notes are available for educators only. Subject code CSS 3: Entrepreneurship.

Universal high-frequency monitoring methods of river water quality in China based on machine learning

The in-situ high-frequency monitoring of total nitrogen (TN) and total phosphorus (TP) in rivers is a challenge and key to instant water quality judgment and early warning. Based on the physical and chemical association between TN/TP and sensor-measurable predictors, we proposed a novel “indirect” measurement method for TN and TP in rivers. This method combines the timeliness of multi-sensor and the accuracy of intelligent algorithms, utilizing 188,629 data sets from 131 water monitoring stations across China. Under 5 algorithms and 4 predictor group scenarios, the results showed that: (1) extra tree regression (ETR) with 6 predictors exhibited the best precision, and the mean determination coefficient (R2) of TN and TP inversion across 131 stations reached 0.78 ± 0.25 and 0.79 ± 0.22 respectively; (2) among 6 potential predictors, the importance degrees of temperature, electrical conductivity, NH4-N, and turbidity were greater than that of pH and DO, and >80 % of stations exhibited acceptable prediction accuracy (R2 > 0.6) when the number of predictors (P) ranged from 4 to 6, which showed good tolerability to predictor variations; (3) the accurate classification rates of water quality standard (ACRws) of all stations based on TN and TP reached 90.41 ± 6.96 % and 92.33 ± 6.41 %; (4) in 9 regions/basins of China, this method showed universal application potential with no significant prediction difference. Compared with laboratory test, water quality automatic monitoring station, and remote sensing inversion, the proposed method offers high-frequency, high-precision, regional adaptability, low cost, and stable operation under rainy, cloudy, and nighttime conditions. The new method may provide important technological support for timely pollutant tracing, pre-warning, and emergency control for river pollution.

Sediment analysis and water quality assessment in the Pixquiac basin: drinking water supply of Xalapa city (Veracruz, Mexico).

Fluvial sediment analysis and water quality assessment are useful to identify anthropic and natural sources of pollution in rivers. Currently, there is a lack of information about water quality in the Pixquiac basin (Veracruz state, Mexico), and this scarcity of data prevents authorities to take adequate measures to protect water resources. The basin is a crucial territory for Xalapa, the capital city of Veracruz state, as it gets 39% of its drinkable water from it. This research analyzed 10 physicochemical parameters and 12 metal concentrations in various rivers and sources during two seasons. Dissolved metals presented average concentrations (µg/L): Al (456.25) > Fe (199.4) > Mn (16.86) > Ba (13.8) > Zn (7.6) > Cu (1.03) > Pb (0.27) > As (0.12) > Ni (0.118) (Cd, Cr and Hg undetectable). Metals in sediment recorded average concentrations (ppm): Fe (38575) > Al (38425) > Mn (460) > Ba (206.2) > Zn (65.1) > Cr (29.8) > Ni (20.9) > Cu (16.4) > Pb (4.8) > As (2.1) (Cd and Hg undetectable). During the rainy season, Water Quality Index (WAWQI) classified stations P17 and P18's water as "unsuitable for drinking" with values of 110.4 and 117.6. Enrichment factor (EF) recorded a "moderate enrichment" of Pb in sediment in P24. Pollution was mainly explained by wastewater discharges in rivers but also because of erosion and rainfall events. Statistical analysis presented strong relationships between trace and major metals which could explain a common natural origin for metals in water and sediment: rock lixiviation.

Evidence of microplastic contamination in the food chain: an assessment of their presence in the gastrointestinal tract of native fish

This research study focused on the primary freshwater surface sources of Khyber Pakhtunkhwa (KP) province, Pakistan—Swat and Kabul rivers. The study aimed to assess microplastic (MP) contamination of fish in the Swat and Kabul rivers. Understanding this contamination is vital for evaluating the environmental and health risks associated with consuming contaminated fish and contributing to the ongoing conservation efforts. The study’s objective was to investigate the presence of MPs in the gastrointestinal tracts (GIT) of fish and to delineate the identified MP types. Samples of local dominant fish (Schizothorax plagiostomus [Swatay] and Racoma labiata [Chunr], Cyprinus carpio [Common Carp], and Clupisoma naziri [Sher Mayai]) were collected, and their body weight and length assessed to gauge the overall health. The GIT samples were processed, digested and filtered before microscopic examination to detect MPs. Subsequently, the identified MPs were subjected to attenuated total reflectance–Fourier transform infrared spectroscopy for characterization by analyzing their absorption bands. Results of the study showed the presence of MPs in fish samples, predominantly identified as polyethylene (PE), with polypropylene (PP) being the subsequently prevalent plastic type, which manifested fish contamination with MPs. The study revealed MP pollution in both Swat and Kabul rivers, with fish ingesting these particles. This poses potential health risks for fish and health of the ecosystem.

Assessment of Natural Bentonite Efficacy for Dye Removal in Textile Wastewater Treatment : Implication for Mitigating River Citarum Pollution

Textile industries contribute significantly to the economy but release harmful pollutants into the environment, especially rivers. The effluent from the textile industry contained toxic dyes that can harm the river ecosystem. Several studies have been conducted to reduce toxic dyes in a river system using bentonite as an adsorbent to reduce river pollution effectively. However, the effectiveness of bentonite still needs to be tested again using textile liquid waste that has not gone through any waste processing at all. Citarum is one of the main rivers on Java Island, which suffers from textile effluent, especially azo dyes which are toxic, mutagenic and carcinogenic which can harm the aquatic ecosystem. Therefore, this study aims to implement natural bentonite as an adsorbent to remove dyes from textile wastewater. We performed a laboratory test to adsorption on bentonite and textile wastewater considering the variation of adsorbent weight of 10 g and 20 g in 100 mL of textile wastewater stirred in an Erlenmeyer flask at room temperature for 0-300 minutes. The initial concentration of textile wastewater used was 10%, 30%, and 50%. We found that the maximum dye removal efficiency was 91.25% with 10% initial concentration treatment, 20 g adsorbent weight, and 60 minutes contact time. Longer contact time will increase the removal efficiency and adsorption capacity, while higher adsorbent dosage will decrease the concentration of dyes in wastewater. Efficient textile wastewater treatment has improved water quality, effectively meeting river water quality standards and environmental regulations.

River chief governance in China: trends and outlooks

The issue of water resources is a perennial topic for achieving human sustainable development goals. Over the last decade, a renewed watershed governance regime, River Chief System emerged to solve the issue of river pollutions in China, and attracted attentions across the world. In this review article, we profiled River Chief System, including its origin, principle and characteristics, and found that the primary feature of River Chief System is its hierarchical structure and the implementation of responsibility. By triangulating bibliometric measurement of the Citespace tool, database of the Web of Science and the China National Knowledge Infrastructure, the development, research trends and hotspots of River Chief System research have been reviewed systematically. The number of publications of River Chief System is showing a significant growing trend, and their foci are diverse: water environmental effects, mechanisms of River Chief System, public participation and supervision and localization of River Chief System, and the implement of “One River, One Policy” plan. Finally, theoretical and practical suggestions for the future study of River Chief System are proposed. This review systematically introduces China’s experience on river management to the world, which is of great significance for the world to fully understand the River Chief System of China and further improve and promote it.

Raising environmental awareness through community-based efforts to clean and preserve the Karang Mumus river, Samarinda City

River pollution, particularly from littering, has long plagued Samarinda City. The Karang Mumus River exemplifies this challenge, with heavy downstream debris and a lack of upstream catchment areas leading to seasonal flooding. This pollution significantly reduces the community's quality of life and hinders sustainable development efforts. To address this, a community service program was initiated to raise environmental awareness through cleaning and maintaining the Karang Mumus River. The program utilized outreach methods to educate the "Save Karang Mumus" (SKM) community about the river's functions and proper environmental practices in the surrounding area. The activity culminated in a river cleaning initiative. Notably, post-program participants expressed a willingness to actively participate in future river cleaning efforts organized by GMSS-SKM. This positive outcome demonstrates the program's success in raising awareness about the importance of protecting the Karang Mumus River environment.

Occurrence, potential sources, and ecological risk assessment of microplastics in the inland river basins in Northern China

Microplastics (MPs) are the pollutants, found widely across various environmental media. However, studies on the MP pollution in urban rivers and the necessary risk assessments remain limited. In this study, the abundance and characteristics of microplastics in a typical urban river were examined to evaluate their distribution, sources, and ecological risks. It was observed that the abundance of MPs in sediments (220–2840 items·kg−1 dry weight (DW)) was much higher than that in surface water (2.9–10.3 items·L−1), indicating that the sediment is the “sink” of river MPs. Surface water and sediment were dominated by small particle size MPs (< 0.5 mm). Fiber and debris were common shapes of MPs in rivers and sediments. The microplastics in river water and sediments were primarily white and transparent, respectively. Polypropylene (PP) and polyethylene (PE) were the major polymers found.