Water Pollution Control Strategies Research Articles

Tracing the source and behaviour of sulphate in karst reservoirs, using stable isotopes and Bayesian isotopic-mixing models.

Increases in sulphate concentrations in natural water bodies can lead to the deterioration of water quality. Human activities, such as coal mining and agricultural fertilisation, can generate sulphate, which can enter water bodies through surface runoff or underground pipelines. Owing to the widespread distribution of coal-bearing strata and an intensification of industrial and agricultural activities, the Pingzhai Reservoir is increasingly at risk of sulphate pollution. In this study, 42 water samples were collected from the Pingzhai Reservoir in April (normal season), July (wet season), and December (dry season) of 2022. Additionally, two precipitation samples, two sewage samples, and two acidic mine drainage samples were collected. Using hydrochemistry, multiple isotopes (δ34SSO4, δ18OSO4, δ13CDIC, and δ18OH2O) and Bayesian isotopic-mixing model methods, we qualitatively and quantitatively determined the source, contribution proportion, and behaviour of SO42- in the Pingzhai Reservoir watershed and evaluated the uncertainty of the estimated results. Isotope analysis and the Bayesian isotope-mixing model results indicated that the sources of SO42- in the Pingzhai Reservoir were coal sulphides and organic sulphur oxidation (64.2%), soil organic sulphur (18.7%), sewage (9.9%), and agricultural sulphur fertiliser (7.2%). The characteristics of karst landforms (thin soil that is easily eroded), combined with periodic fluctuations in water level (hydrofluctuation belts) in reservoirs, resulted in the release of organic matter from soil to water. The proportion of SO42- sources of coal sulphide and organic sulphur oxidation in the river was lower than that in the reservoir area, whereas the proportion of the SO42- sources of soil organic sulphur, sewage, and agricultural sulphur fertiliser was greater than that in the reservoir area. Isotope evidence and the aerobic conditions in water indicated that bacterial sulphate reduction processes did not play a major role. The uncertainty index (UI90) indicated that the contributions of agricultural sulphur fertiliser and sewage manure to SO42- were relatively constant. This study provides a reference for the protection of water environments and for the development of water pollution control strategies in the karst areas of southwestern China.

Spatiotemporal Analysis and Risk Prediction of Water Quality Using Copula Bayesian Networks: A Case in Qilu Lake, China

Lake water pollution under anthropogenic influences exhibits characteristics of high uncertainty, rapid evolution, and complex control challenges, presenting substantial threats to ecological systems and human health. Quantitative risk prediction provides crucial support for water quality deterioration prevention and management. This study employed the Copula Bayesian Network model to conduct a comprehensive risk assessment of water quality in Qilu Lake, China (2010–2020), incorporating inter-indicator correlations and multiple uncertainty sources. Analysis revealed generally “worse” water quality conditions (5.10 ± 1.35) according to established index classifications, with predicted probabilities of reaching “deteriorated” status ranging from 11.80% to 47.90%. Significant spatial and temporal variations in water quality and pollution risk were observed, primarily attributed to intensive agricultural non-point source loading and water resource deficiency. The study established early warning thresholds through key indicator concentration predictions, particularly for the southern region where “deteriorated” risk levels corresponded to specific ranges: TN (3.42–8.43 mg/L), TP (0.07–1.29 mg/L), and CODCr (27.75–67.19 mg/L). This methodology effectively characterizes lake water quality evolution while enabling risk prediction through key indicator monitoring. The findings provide substantial support for water pollution control strategies, risk management protocols, and regulatory decision-making for lake ecosystem administrators.

Barriers to Water, Sanitation and Hygiene Practices in Mutare District, 2022

Background: Sanitation and hygiene are extremely important for survival, development and health. Inadequate sanitation expose people to water, sanitation and hygiene related diseases. Mutare district has been increasingly recording unsatisfactory bacteriological tests from the first quarter of 2019 to the first quarter of 2023 and water-borne infections have been increasing. We evaluated the WASH program in Mutare district. Methods: We conducted a program evaluation using logical framework approach. Twenty-one health facilities were sampled and 63 participants recruited. An interviewer-administered questionnaire was used to assess healthcare worker (HCW) knowledge and review of environmental records was done. Resources required for the health facilities WASH programs were assessed using a checklist. Frequencies, means and proportions were generated. Results: The median years of service of HCW was 9 years. The district lacked land and water pollution control strategies and consumables for water bacteriological testing. Aquatabs were in limited supply. Some of the visited health facilities (6/21) poorly segregated waste, although all the HCW were mentored on WASH activities. Conclusion: Inadequate water test kits and other resources compromises the performance of the WASH program. Segregation of waste appropriately reduces the risk of infection and injuries among the waste handlers.

Water Hyacinth Leaves Are an Efficient, Green, and Cost-Effective Biosorbent for the Removal of Metanil Yellow from Aqueous Solution: Kinetics, Isotherm, and Thermodynamic Studies.

Excessive water hyacinth growth in aquatic environments and metanil yellow (MY) dye in industrial wastewater pose severe environmental and public health challenges. Therefore, this study evaluated the effects of various process factors on batch MY biosorption onto water hyacinth leaves (LECs) and MY biosorption kinetics, equilibrium, and thermodynamics. The optimal pH for MY biosorption by LECs was 1.5-2.0. The initial MY concentration affected the equilibrium MY biosorption capacity but not the LEC particle size and solution temperature. However, the LEC particle size and solution temperature affected the MY biosorption rate; the biosorption rate was higher at a lower particle size (0.15-0.3 mm) and a higher temperature (62 °C) than at higher particle sizes and lower temperatures. The pseudo-second-order model adequately described the biosorption kinetics of MY by LECs at the different levels of the process factors, whereas the Sips and Redlich-Peterson models satisfactorily represented the biosorption isotherm of MY. The Sips model predicted a maximum MY biosorption capacity of 170.8 mg g-1. The biosorption of MY by LECs was endothermic and not spontaneous. These findings demonstrate that LECs exhibit great potential for bioremediating MY-contaminated wastewater, thereby providing valuable insights for effective water treatment and pollution control strategies.

Long-term trend prediction of surface water quality of two main river basins of China using Machine Learning Method

Rivers play a crucial role as sources of freshwater worldwide. The Yangtze and Yellow rivers, often regarded as the lifelines of China, significantly contribute to the nation's economy through their abundant water resources. Maintaining the quality of water in these river basins is essential for both human health and a thriving ecological system. This study intended to assess the historical water quality of China's two mother river basins including the Yangtze River, and the Yellow River. This assessment analyzes the historical dissolved oxygen, Ammonium nitrogen, and permanganate, and calculates comprehensive water quality identification (CWQII) values to find the trend and predict future values using a Machine learning model. To evaluate the stationarity of historical data, different tests and measures have been taken such as ADF and KSPP to test stationarity. Autocorrelation and partial autocorrelation also have been performed to understand the nature of the data. According to the SARIMA model, the Mean Absolute Percentage Error (MAPE) for the CWQII was 9.1% for the Yangtze and 13.3% for the Yellow River. In contrast, the LSTM model yielded MAPE values of 7% and 14%, respectively. For Dissolved Oxygen (DO) prediction, the SARIMA model showed MAPEs of 8.9% for the Yangtze and 9.87% for the Yellow River, while the LSTM model resulted in 8% and 16%, respectively. The current and future forecasting of CWQII values suggest that, based on model forecasts, the water quality in the Yellow River basin may be poorer compared to the Yangtze River basin This study might help the government, researchers, and other stakeholders to take proper steps to develop water pollution control strategy.

Analysis of Water Quality Pollution Index Asahan river in Tanjungbalai City

The Asahan River, located in the Tanjungbalai city area, is used for plantation, agriculture, animal husbandry activities, toilet washing facilities, hospitals, hotels, settlements, and industry causing the decrease water quality of Asahan River. The purpose of this study was to analyze the water quality and status of the Asahan River water quality in the Tanjungbalai City Area and develop a pollution control strategy that needs to be implemented to prevent a decrease in the Asahan River water quality in the Tanjungbalai City Area. Purposive sampling technique as used to determine the sampling station. In this study, there were 6 sampling stations based on the activities of the local community with 3 repetitions of sampling. The data analysis techniques from this study are Water Quality Analysis using the Pollution Index (IP) Method and Water Pollution Control Strategy Analysis. The results of water quality analysis based on the pollution index on Asahan river water in Tanjungbalai City show that the average water pollution index is in the moderately polluted category. The maximum of river water pollution index results were at station 2 is 9,086 and the minimum of river water pollution index results were at station 5 is 6,111.Water pollution occurs due to the parameters of phosphate, detergent, oil and grease, and total coliform which have exceeded the quality standard threshold based on Government Regulation of the Republic of Indonesia Number 21 of the year 2022 concerning Management of Water Quality and Control of Class I Water Pollution.Keywords:Asahan RiverWater pollution IndexWater Quality

The effects of wind-wave disturbances on sediment resuspension and phosphate release in Lake Chao

As a typical shallow lake with a wind-generated flow, the resuspension state of sediment and phosphorus release under wind field disturbance plays an important role in controlling lake eutrophication in Lake Chao. In this study, we proposed a combination of experimental analysis of dynamic disturbances, wind-wave disturbance shear stress calculation, and model simulation (experimental-calculative-modeling) to quantitatively investigate the effects of wind-wave disturbances on the resuspension state of Lake Chao bottom sediment and phosphorus release and distribution. The results showed that the release rate of phosphorus from the Lake Chao bottom sediment was affected by the wind field and bottom sediment content, which varied significantly spatially and showed some difference between different seasons. Under the condition of sufficient water body disturbance, the substrate in the Western Lake area of Lake Chao mainly adsorbed phosphate from the water body, while the substrate in the Central Lake area and the Eastern Lake area adsorbed phosphate along with the release. The magnitude of the phosphorus release rate due to sediment resuspension was mainly affected by wind speed, and the distribution of phosphorus content was influenced by the circulation generated by different dominant wind directions. The wind-wave disturbances have a significant effect on the spatial and temporal distribution of phosphorus in Lake Chao, and the proposed experimental-calculative-modeling ensemble can provide relevant technical support for the study of water pollution control strategies and comprehensive remediation and management of Lake Chao.

Environmental health risk assessment of urban water sources based on fuzzy set theory

Abstract Water pollution and protection of water resources have become an urgent task for humanity today and are also important components of environmental risk assessment. In response to the problems of high risk level and low risk credibility in the current environmental health risk assessment of urban water sources, this article aims to use fuzzy set theory to comprehensively evaluate the environmental quality and quickly monitor the safety of urban water sources. Therefore, this article analyzed the health factors of the urban water source environment and then studied the content and uncertainty analysis of health risk assessment. Finally, it constructed a health risk assessment system and proposed corresponding water environment protection strategies. In the experimental section, the risk level and risk credibility of the water environment were analyzed. Through comparison, it was found that the risk level in the new water environment health risk assessment was 0.16 lower than that in the traditional water environment health risk assessment, and the risk credibility was 0.11 higher than that in the traditional water environment health risk assessment. The water quality monitoring effect in the new water environment health risk assessment was 7.3% higher than that in the traditional water environment health risk assessment, The health hazard effect is 8.2% lower than traditional water environment health risk assessment. In summary, water environment health risk assessment plays an important role in protecting the water source environment. Health risk assessment of the water environment helps to reduce water pollution, improve water quality, and ultimately improve human health. Moreover, using fuzzy set theory makes it easier to comprehensively and efficiently evaluate the water environment. The innovation of this article lies in paying attention to the importance of fuzzy set theory in water pollution risk assessment and applying fuzzy technology to water pollution control strategies, to better improve water quality and optimize water source environmental health risk assessment methods.

Review of water quality index models as river quality evaluation tool: insight from various rivers in Indonesia

As industrial activities grow and increase, it is directly proportional to the wastewater produced, which is disposed of into the river. One of the calculation models commonly used for evaluating surface water quality is the water quality index (WQI). The method produces uncertainty in the conversion and is site specific dependent. The data collected for the last five years used a comparative method to assess the status classification of those rivers’ quality. In addition, this study also aims to classify the river quality status and evaluate the WQI model in determining the impact of industrial activities on Sumatra Island and Kalimantan Island, the five longest rivers in Indonesia. This paper uses the WQI to review the water quality condition of Indonesia’s five longest rivers, i.e., Kapuas River, Mahakam River, Barito River, Batanghari River, and Musi River, where the community heavily uses these rivers for their daily needs. This review study concluded that the WQI of a river could vary depending on the measurement data used in calculating the WQI value. The data describing the WQI of a river is a momentary WQI or periodic WQI. The study is expected to be used as a basis for developing a sustainable water pollution control strategy to maintain the grade status of a river according to its classification.

Impact of Cement Industry on Water Quality in the Athi River, Machakos County, Kenya

Cement is one of the most often used building materials and its production is increasing globally. Simultaneously, cement production is energy intensive and produces harmful emissions such as gases, noise, and wastewater. The aim of the study was to determine the impact of the cement industry on water quality in Athi River, Kenya. The cement industry had significant impacts on water physicochemical variables such as temperature (p = 0.0003), conductivity (p = <0.001), total suspended solids (p = <0.001), ammonium (p = 0.04), pH (p = 0.02), and turbidity (p = 0.0001). Mean values for physicochemical variables such as conductivity, total suspended solids, total dissolved solids, turbidity, and lead exceeded the limits set by World Health Organization (WHO) for drinking water quality. Water pollution control strategies need to be implemented to improve water quality in the Athi River and prevent further deterioration of the environment. Future studies should evaluate the effect of the cement industry on other water resources (e.g., groundwater) and air quality

Source apportionment of heavy metal(loid)s in sediments of a typical karst mountain drinking-water reservoir and the associated risk assessment based on chemical speciations.

As important place for water storage and supply, drinking-water reservoirs in karst mountain areas play a key role in ensuring human well-being, and its water quality safety has attracted much attention. Source apportionment and ecological risks of heavy metal(loid)s in sediments of drinking-water reservoir are important for water security, public health, and regional water resources management, especially in karst mountain areas where water resources are scarce. To expound the accumulation, potential ecological risks, and sources of heavy metal(loid)s in a drinking-water reservoir in Northwest Guizhou, China, the surface sediments were collected and analyzed based on the combined use of the geo-accumulation index (Igeo), sequential extraction (BCR), ratios of secondary phase and primary phase (RSP), risk assessment code (RAC), modified potential ecological risk index (MRI), as well as the positive matrix factorization methods. The results indicated that the accumulation of Cd in sediments was obvious, with approximately 61.9% of the samples showing moderate to high accumulation levels, followed by Pb, Cu, Ni, and Zn, whereas the As and Cr were at low levels. A large proportion of BCR-extracted acid extractable and reducible fraction were found in Cd (72.5%) and Pb (40.3%), suggesting high bioavailability. The combined results of RSP, RAC, and MRI showed that Cd was the major pollutant in sediments with high potential ecological risk, while the risk of other elements was low. Source apportionment results of heavy metal(loid)s indicated that Cd (75.76%) and Zn (23.1%) mainly originated from agricultural activities; As (69.82%), Cr (50.05%), Cu (33.47%), and Ni (31.87%) were associated with domestic sources related to residents' lives; Cu (52.36%), Ni (44.57%), Cr (34.33%), As (26.51%), Pb (24.77%), and Zn (23.80%) primarily came from natural geological sources; and Pb (47.56%), Zn (22.46%) and Cr (13.92%) might be introduced by mixed sources of traffic and domestic. The contribution ratios of the four sources were 18.41%, 36.67%, 29.48%, and 15.44%, respectively. Overall, priority control factors for pollution in relation to agricultural sources included Cd, while domestic sources are primarily associated with As. It is crucial to place special emphasis on the impacts of human activities when formulating pollution prevention and control measures. The results of this study can provide valuable reference and insights for water resources management and pollution prevention and control strategies in karst mountainous areas.

Analisis Kualitas Air di Sungai Marbau

This study aims to analyze the quality of river water and the water quality status of the Marbau watershed in North Labuhanbatu Regency based on water quality criteria and to formulate a pollution control strategy that needs to be implemented. The method used is a quantitative descriptive method by analyzing the status of river water quality based on the pollution index. The results showed that the P1 value of Marbau river water ranged from 0.94 to 1.82. The recommended pollution control strategies are: 1) maintaining river protection zones involving environmental cadres and green communities in monitoring; 2) monitoring and controlling water pollution along the river; 3) improve river water quality monitoring; 5) supervision of the discharge of waste water into rivers; 4) granting permits for disposal of wastewater (IPLC) into rivers must pay attention to the condition of the capacity to accommodate river pollution loads and enforce environmental law against business actors who violate established environmental quality standards. In conclusion, the quality of the Marbau river has decreased with the water quality status being slightly polluted. The recommendations for water pollution control strategies that need to be implemented are progressive strategies.
 Keywords: Water Quality, North Labuhanbatu, Marbau

Influence of nitrogen inputs, dam construction and landscape patterns on riverine nitrogen exports in the Yangtze River basin during 1980–2015

A quantitative understanding of different N sources and the factors controlling riverine N fluxes is critical for optimizing water pollution control strategies. However, the lack of a comprehensive understanding of N pollution legacy effects and human alteration of landscapes (e.g., dam construction and land use/land cover) hinders development of efficient N management strategies. This study integrated long-term (1980–2015) net anthropogenic nitrogen inputs (NANI) and different forms of N exports, hydroclimate data, dam construction and landscape metrics to elucidate N sources and the factors controlling N fluxes in the Yangtze River basin (YRB). Over the 36-year study period, annual NANI in the YRB increased from 4166 to 8571 kg N km−2 yr−1. Riverine concentrations of total nitrogen (TN), dissolved inorganic nitrogen (DIN) and dissolved organic nitrogen (DON) increased ∼ 3-fold, ∼3-fold and ∼ 36-fold during 1980–2015, respectively, whereas riverine particulate nitrogen (PN) decreased by ∼ 90 %. Such long-term riverine N export dynamics were driven by elevated NANI, landscape configuration change and dam construction activities. Inclusion of these variables in multiple linear regression models explained 91 %, 83 % and 96 % of the annual variability in riverine DIN, DON and PN fluxes, respectively. Estimated riverine TN flux from sum of predicted DIN, DON and PN fluxes showed high agreement with measured values (R2 = 0.92, Nash–Sutcliffe coefficients = 0.91), indicating strong efficacy for the developed regression models. Separation of annual riverine N exports into current year NANI versus legacy source contributions indicated that legacy sources contributed ∼ 49 % (26–82 %), 51 % (<1–78 %), 95 % (87–98 %) and 56 % (36–86 %) of riverine DIN, DON, PN and TN exports, respectively. The release of legacy N from the landscape is associated with increases in dam construction, urban density, and the number of small area farm operations between 1980 and 2015. This study highlights the potential of aggregating multiple historical N input datasets, along with changes in land use and river regulation to model long-term riverine N export dynamics. The results of the study provide a foundation for developing integrated watershed N management strategies that address both current and legacy N pollution.

Remote sensing monitoring of total nitrogen and total phosphorus concentrations in the water around Chaohu Lake based on geographical division

Remote sensing is useful for quantifying water-quality parameters for managing inland water systems. However, the single water-quality retrieval model usually has poor applicability in large regions. To solve the issue of low retrieval accuracy of water-quality parameters in inland water, the study area herein is geographically divided into rural water and urban water according to the proportion of land-use types in the riparian zones. Furthermore, the machine-learning regression algorithms are used to construct the retrieval models suitable for the total nitrogen (TN) and total phosphorus (TP) concentrations based on the measured water-quality data and the simultaneous Sentinel-2 Multispectral Imager (MSI) images. Additionally, the optical retrieval models are applied to the MSI images acquired on different dates to analyze the variations of TN and TP concentrations in the water around Chaohu Lake of China. The results show that the three accuracy indices of determination coefficient (R2), mean square error (MSE), and mean absolute percentage error (MAPE) of the TN concentration retrieval models for rural water and urban water were 0.67, 0.37 mg/L, and 36.81%, and 0.78, 0.34 mg/L, and 8.34%, respectively, while those of the TP concentration retrieval model for rural water and urban water reached 0.46, 0.0034 mg/L, and 38.60%, and 0.58, 0.018 mg/L, and 37.57%, respectively. The accuracy of the TN and TP concentration retrieval model constructed using geographical division is significantly better than that which does not use geographical division. According to the retrieval results from MSI images, the TN and TP concentrations in urban water are higher than those in rural water. TN and TP concentrations in urban water are stable throughout the year and peak in December, while those of rural water are highest in March and lowest in November. The method proposed in this study can provide a new idea for improving the retrieval accuracy of water-quality parameters in different water bodies in a large-scale region, and the relevant conclusion can provide a theoretical basis for water pollution control and prevention strategies in agricultural basins.

Water Quality Status of Jatigede Reservoir Sumedang Regency, West Java

With the captured fisheries sector as a livelihood for residents around Jatigede, it is feared that water quality will decline. Another function of the Jatigede Reservoir is to irrigate irrigation canals, control floods, source PLTA power, and raw water to serve the people of Sumedang, Indramayu, and Cirebon city. The intended purpose is to determine the quality of water in the Jatigede Reservoir. This research was carried out in Jatigede Reservoir from November 2020 to August 2021, using the survey method. The method of determining the location used a purposive sampling method, carried out at five stations representing Jatigede Reservoir. The water quality parameters used are temperature, pH, dissolved oxygen, and brightness. The results of observations of water quality in Jatigede Reservoir with temperatures ranging from 28°C-29°C, pH ranging from 6.67–8.35, dissolved oxygen ranging from 6.8–7.83 mg/l and brightness ranging from 70-93.8 cm indicate that the water quality of the Jatigede Reservoir is still categorized into good water quality and is ideal for capture fisheries sector activities in the Jatigede Reservoir. The results of the status of water quality in the waters of the Jatigede Reservoir are included in the category of Fulfill Quality Standards to Lightly Polluted, and the average Pollution Index value ranges from 1.75 to 3.01 in class II water quality standards and 0.86-1.94 in class III water quality standards. Water quality in Jatigede Reservoir during the research was influenced by the input of river flow in the form of organic and inorganic waste. Water pollution control strategies can be carried out by increasing the inventory and identification of pollutant sources, improving waste management, determining the capacity of the pollution load, increasing knowledge and community participation in waste management, increasing supervision of wastewater development, and improving water quality monitoring.

Kualitas Air Sungai

This study aims to analyze the water quality of the Barumun river in Pinang City based on water quality criteria and formulate a pollution control strategy that needs to be implemented. The method used is descriptive and quantitative by analyzing river water quality status based on the pollution index. The results showed that the PI value of Barumun river water ranged from 0.82 to 1.71. The recommended pollution control strategies are: 1) maintaining river border protection zones involving environmental cadres and green communities in monitoring; 2) supervision and control of water pollution along the river; 3) improving monitoring of river water quality and supervision of wastewater discharge into rivers; 4) the granting of a wastewater disposal permit (IPLC) to the river must pay attention to the condition of the capacity of the river's pollution load capacity and enforce environmental laws against business actors who violate the established environmental quality standards. In conclusion, the Barumun River in Kota Pinang has decreased in quality, with the status of water quality being lightly polluted. The recommendations for water pollution control strategies that need to be implemented are progressive strategies.&#x0D; Keywords: Water Quality, Water Pollution Control, Water Quality Status

Strategi Pengendalian Pencemaran Sungai Siak yang Berkelanjutan Menggunakan Pendekatan Multi Criteria Decision Making (MCDM)

The main objective of the research is to establish a sustainable Siak River pollution management strategy, in an effort to accelerate (quick win) the strategic policy of Siak River pollution management which is one of the National Strategic category rivers located in the Sumatra Region based on Presidential Decree No. 12 of 2012 concerning the Determination of the River Basin, because the Siak River has a very large function and role in regional and economic development both locally, regionally and nationally. The approach method used is Multi Criteria Decision Making (MCDM) with the selected method of Analytical Hierarchy Process (AHP). The primary data is in the form of questionnaire data with the aim of being assessed by experts (expert judgment) who are considered competent in assessing the processing of Siak River pollution. Seven respondents identified who have the potential and are representative to contribute to obtaining expert judgment recommendations consist of Universities represented by the University of Riau (UR), the Riau Province Environmental Agency (BLH), the Sumatran Ecoregion Development Control Center, Non-Governmental Organizations (NGO) Jikalahari, Center for Watershed Management (BPDAS) Indragiri Rokan. Regional Research and Development Agency for Riau Province and the River Basin Center (BWS) III Sumatra. The main results of the study stated that the Siak River water pollution control strategy using the AHP approach sequentially was to rearrange the spatial function, determine the pollution load capacity (DTBP), coordination of stakeholder synergies, program socialization and counseling, supervision and monitoring, law enforcement and development. Wastewater Treatment Plant (WTP).

Pollution Index Analysis and Water Pollution Control Strategy in Berenyok River, Tanjung Karang, Mataram City

Berenyok river is one of the water sources in Tanjung Karang, Mataram city, categorised as Class 2 for its designation. Thus, preserving the quality of water in the Berenyok river is crucial. This study aims to determine the water quality, calculate the Pollution Index (PI), and set control strategies for the Berenyok river. The study uses quantitative methods such as laboratory analysis for the water quality and PI calculation using a formula based on the Decree of the Minister of Environment No.115/2003 on determining water quality status. Meanwhile, the Strengths, Weakness, Opportunities, and Threats (SWOT) analysis generates recommendations for water pollution control strategies. The sampling locations are located in two sampling points (upstream and downstream of the Berenyok river) during bright daylight and the river's normal flow. Based on analysis results, the Berenyok river is defined as lightly polluted as the concentrations of several chemical parameters exceed the maximum limit, such as BOD, and PO3-P. It is also verified by high concentration of total coliform, namely 540,000 MPN/100mL (upstream) and 1,600,000 MPN/100mL (downstream). Thus, recommendations for water pollution control strategies are substantial for the Berenyok river.

Human activities changed organic carbon transport in Chinese rivers during 2004-2018

Rivers serve as regulators of global climate by releasing greenhouse gases, burying particulate carbon, and connecting different ecosystem carbon pools. However, long-term organic carbon (OC) transport features across different Asian rivers are not well known due to unavailable data. Based on routinely monitored environmental and hydrological data during 2004-2018, this study investigated the spatiotemporal variations in dissolved (DOC) and particulate OC (POC) transport across 41 rivers in China. Across different rivers, both DOC (1.35 – 16.8 mg/L) and POC (0.27 – 4.48 mg/L) concentrations covered wide ranges. The DOC content was high in the north and low in the south, with significantly higher (t test, p < 0.01) values for rivers north of 30°N (5.39 ± 3.66 mg/L vs. 2.39 ± 1.14 mg/L). Human activities greatly influenced the riverine DOC and POC distributions. The riverine ammonia nitrogen (NH+ 4-N) content was positively correlated with DOC (r = 0.81 and p < 0.01) and explained 85.59% of its spatial variation. High vegetation coverage had significant effects on decreasing the riverine POC content, with r = -0.55 and p < 0.05. During 2004-2018, water pollution prevention and control strategies decreased DOC concentrations in 60.98% of rivers; meanwhile, anthropogenic vegetation restoration and dam construction led to POC content decreases in 90.48% of rivers. Importantly, along with DOC and POC changes, increasing DOC/POC ratios were found in 90.48% of the rivers, with 42.86% being significant, which indicated that Chinese rivers are losing their Asian features of low DOC/POC ratios due to artificial disturbance. This study is significant for accurately quantifying greenhouse gas emissions, carbon burial, and OC export to estuaries by Chinese rivers.

Identification of rainy season nitrogen export controls in a semi-arid mountainous watershed, North China

A comprehensive understanding of the nutrient export process and export controls is demanded effective pollution mitigation in fragile riverine ecosystems. In this study, behaviors of the full range of nitrogen (N) under stormflow (5-events) and baseflow (2-events; before and after the rainy season, multiple sites) were assessed to explore N export controlling mechanisms according to the identified main components causing the changes in N exports, N transport pathways, seasonal trends, and nutrient supply watershed regions through the 2020 rainy season in a semi-arid mountainous watershed, northern China. Results showed increments in riverine dissolved organic-N (DON) and particulate-N (PN) loadings as the leading cause of N flux and composition changes through the rainy season, although nitrate-N (NO3-N) contributed 69.6% of total-N (TN). Storm runoff generated 3-fold and 4-fold average increments in DON and PN fluxes. DON and PN shared 1–66% (18.1%) and 1–44% (9.7%) of TN through storms, registered consistency in behavior, mainly originated from near-stream soil, and were primarily transported by shallower subsurface flow. Our results broaden the understanding of PN delivery in catchment wetting-up periods by highlighting the decoupling of primary origins/transport pathways of PN from sediments. Results suggested hydrological functioning parallel to the catchment wetting-up as the principal governor of storm N evolution; soil moisture levels build up in the early rainy season, soil water runoff dominance during peak discharge fluctuations, groundwater runoff dominance at the end of the rainy season. Cumulative rainfall and antecedent soil moisture exerted more significant control over storm N exports than individual rainfall features. The assessment of N behaviors through river network disclosed watershed regions responsible for excessive N delivery and influences of unsustainable agriculture, sewage treatment work, and damming on natural riverine N fluxes. These findings could be useful references for the formulation of water pollution control strategies in the future.