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With the increasing demand for crops, the excessive application of fertilizers has gradually become a significant factor affecting water quality. Therefore, studying the relationship between agricultural fertilizer runoff and water quality is crucial for the sustainable development of agricultural production. The present study sets up a new dynamic model of nitrogen fertilizer loss, introducing variables such as precipitation, fertilization application during dry and rainy seasons, and their lagged and interaction terms. The paper analyzed the issue of fertilizer runoff under the complex interactions of various factors, including spatial and temporal scales and climatic conditions, and explored the relationship between agricultural activities and water quality changes in the context of sustainable development. Due to Hainan Island's independent river system, which is free from transboundary pollution, and its low level of industrial pollution, it provides an excellent sample for assessing the impact of agricultural non-point source pollution on water quality. Based on watershed monitoring data from Hainan Island, this study draws the following conclusions: 1. Precipitation exhibits a pronounced seasonal influence on total nitrogen concentration. 2. Nitrogen fertilizer enters into water bodies through precipitation, resulting in a lag effect on total nitrogen concentration. 3. The influence of grain and tropical crops on nitrogen loss is less significant, while cash crops will trigger the nitrogen overloading of rivers in scenarios where they account for a high proportion of the planting structure of the sown area. [ABSTRACT FROM AUTHOR]

Under the current increasingly serious water pollution situation in urban, the comprehensive treatment and protecting measures in urban small catchment are the necessary step to the water pollution treatment, not only focus on the water bodies themself. In this paper, the Luojiagang river channel and its catchment in Wuhan, which has been heavily impacted by water pollution, are taken as an example for the comparative assessment of pollution control measures in order to explore the effective and sustainable schemes including the LID (Low Impact Development---LID) by using SWMM model (Storm Water Management Model---SWMM). Through the comparison of pollution treatment measures based on scenarios simulation with the baseline scenarios, it was found that the reduction effects of pollutant peak concentrations at the outlet node of Luojiagang River had the decreasing order of: the combined measures (COS) > LID control > the water diversion from Donghu Lake (WAD) > the sewage treatment (SET) > the sediment dredging (SED), and the reduction effects of total pollutant load had the decreasing order of: LID > COS > SET > SED > WAD. The results show that the control of non-point source pollution is the key for the improvement of water quality in Luojiagang River, and LID plays important role in the reduction of both pollutant peak concentrations and load. This study has the implication for the decision making of the water pollution controlling schemes in urban small catchment. [ABSTRACT FROM AUTHOR]

Due to the typically high flow rate of nozzles on large sprinkler machines, direct use for pesticide application can lead to pesticide waste and non-point source pollution. To fulfill the multifunctional needs of large sprinkler machines for irrigation, fertilization, and pesticide application, this study installed atomizing micro-sprinklers on the machines to enable their pesticide application capabilities. Based on the spraying patterns of the atomizing micro-sprinklers, three types were selected for this study: hollow cone, solid cone, and fan-shaped micro-sprinklers. Three working pressure levels were set at 0.2 MPa, 0.3 MPa, and 0.5 MPa, with the height of the micro-sprinklers above the ground set at three levels: 0.8 m, 1.2 m, and 1.5 m. A completely randomized design was used for the experiment, which included hydraulic performance tests and software simulation. The results indicated that the spray volume of the hollow cone, solid cone, and fan-shaped atomizing micro-sprinklers approximately presented a hollow conical, solid conical, and normal distribution, respectively. The spray intensity (average and maximum values) of the atomizing micro-sprinklers increased with the increase in pressure, while the median showed an initial increase followed by a decrease as pressure increased. Under the same pressure conditions, the spray intensity of the different atomizing micro-sprinklers decreased with the increase in height above the ground, while the spray width increased with height. By comparing the spraying characteristics of micro-sprinklers with various patterns, large sprinkler machines can select atomizing micro-sprinklers in different spraying statuses according to actual conditions and determine the optimal height of the atomizing micro-sprinklers above the ground to achieve efficient and uniform pesticide application effects. This reduces the evaporation and drift loss of liquid medicine. The research findings provide a scientific basis for achieving the pesticide application function of large sprinkler machines and expanding their usage capabilities. [ABSTRACT FROM AUTHOR]

Groundwater serves as a crucial resource, with its quality significantly impacted by both natural and human-induced factors. In the highly industrialized and urbanized Yangtze River Delta region, the sources of pollutants in shallow groundwater are more complex, making the identification of groundwater pollution sources a challenging task. In this study, 117 wells in Wujiang District of Suzhou City were sampled, and 16 groundwater quality parameters were analyzed. The fuzzy synthetic evaluation method was used to assess the current status of groundwater pollution in the study area; the principal component analysis (PCA) was employed to discern the anthropogenic and natural variables that influence the quality of shallow groundwater; and the absolute principal component scores–multiple linear regression (APCS-MLR) model was applied to quantify the contributions of various origins toward the selected groundwater quality parameters. The results indicate that the main exceeding indicators of groundwater in Wujiang District are I ( 28 % ), N H 4 - N ( 18 % ), and Mn ( 14 % ); overall, the groundwater quality is relatively good in the region, with localized heavy pollution: class IV and class V water are mainly concentrated in the southwest of Lili Town, the north of Songling Town, and the south of Qidu Town. Through PCA, five factors contributing to the hydrochemical characteristics of groundwater in Wujiang District were identified: water–rock interaction, surface water–groundwater interaction, sewage discharge from the textile industry, urban domestic sewage discharge, and agricultural non-point source pollution. Additionally, the APCS-MLR model determined that the contributions of the three main pollution sources to groundwater contamination are in the following order: sewage discharge from the textile industry ( 10.63 % ) > urban domestic sewage discharge ( 8.69 % ) > agricultural non-point source pollution ( 6.26 % ). [ABSTRACT FROM AUTHOR]

Climate change scenarios have been used to evaluate future climate change impacts and develop adaptation measures to mitigate potential damage. This study investigated strategies to reduce nonpoint source loads in an agriculturally dominated watershed and adapt to climate change despite uncertainty. We also investigated strategies for adapting to future meteorological conditions characterized by uncertainty. We utilized the latest future climate change scenarios—shared socioeconomic pathways—and explored measures to reduce nonpoint source loads by implementing nonpoint pollution abatement facilities in a watershed model. The simulation results indicate that the future frequency of rainfall events may decrease based on observations and the types and features of rainfall events in the scenarios. However, the variability of runoff loads in the context of future climate scenarios may increase because of factors influencing surface runoff, including the amount and intensity of rainfall. Nonpoint source loads are expected to exhibit high uncertainty in the future. Finally, the optimal solution can be determined through a simulated evaluation of the cost–benefit of installing the abatement facilities, considering the abatement efficiency and maintenance period. Overall, implementing effective management practices is crucial for reducing nonpoint source loads resulting from agricultural activities while adapting to increasingly variable meteorological conditions. [ABSTRACT FROM AUTHOR]

Non-point source (NPS) pollution has a complex formation mechanism, and identifying its primary controlling factors is crucial for effective pollution treatment. In this study, the Baixi Reservoir Watershed, characterized by low-intensity development, was selected as the study area. A new methodology combining the Soil and Water Assessment Tool (SWAT) with the Random Forest (RF) algorithm was proposed to comprehensively identify the primary controlling factors of NPS pollution and analyze the interaction between factors. The results of the validated SWAT model showed that the annual intensity of total nitrogen (TN) load range was 0.677–11.014 kg ha−1 yr−1, and the total phosphorus (TP) load per unit area range was 0.020–0.110 kg ha−1 yr−1. Loads of sediment, TP, and TN exhibited significant seasonal variations, particularly in the Baixi basin, where sediment yield had the highest absolute change rate, with a value of up to 232.26. Random Forest models for TN and TP displayed high accuracy (R2 > 0.99) and robust generalization ability. Fertilization, sediment yield, and terrain slope were identified through RF models as the primary factors affecting TN and TP. By graphing partial dependency plots (PDPs) based on the results of the RF models to analyze the interaction between factors, the findings suggest a strong synergistic effect of two combined factors: fertilization and sediment yield. When fertilizer application exceeds 15 kg ha−1 yr−1 and sediment yield exceeds 3 kg ha−1 yr−1, there is a sharp increase in nitrogen and phosphorus load. Through the identification and analysis of the primary controlling factors of NPS pollution, this study provides a solid scientific foundation for developing effective watershed management strategies. [ABSTRACT FROM AUTHOR]

Like many small island communities, the U.S. Virgin Islands (USVI), an unincorporated territory of the U.S., is naturally freshwater scarce. In recent decades, rapid land development in the USVI has increased water demand considerably, exerting extra pressure on freshwater resources. Freshwater quantity and quality data for the USVI are very scarce and scattered, which limits freshwater management capabilities. We draw attention to this information deficit and discuss its implications by reviewing the current state of knowledge of surface and groundwater quantity and quality for the USVI. Our review confirms that long‐term records of surface and groundwater quantity and quality are limited and unreliable. For example, streamflow was most recently monitored in 2006, and the most extensive surface water quality records are from the 1960s and 1980s. Since 2016, mean groundwater levels have been recorded daily, but only for three wells (one on each island of the USVI). Importantly, this lack of information threatens water security for the territory and limits our understanding of how development has impacted water quality and availability over time. This could be addressed using models, such as a groundwater recharge model, in combination with remote sensing and updated field data (i.e., streamflow, groundwater, and ecohydrological characterizations of land use change). [ABSTRACT FROM AUTHOR]

Fertilizers are an essential input in agriculture as they can enhance crop yields. However, their use also poses significant environmental risks. To thoroughly explore the intensity of fertilizer use and its potential threats to the ecological environment, this study analyzed the environmental risks of fertilizer use from a temporal and spatial perspective based on fertilizer application data in China from 1978 to 2022. Additionally, the contribution of fertilizer application in Chinese farmland to greenhouse gas N2O emissions was quantified using IPCC emission factor methodology. The results indicated that fertilizer application intensity and N2O emissions in China initially increased and then decreased from 1978 to 2022. Despite the implementation of various fertilizer control measures at the policy level, such as the Zero Growth of Fertilizer Action in 2015 and the Efficiency-Increasing Action for Reducing Fertilizer Use in 2022, the intensity of fertilizer application in China still exceeded international safety standards by 1.33-fold in 2022, reaching 298.79 kg/hm2. Furthermore, N2O emissions amounted to 50.17 × 104t, accounting for 16% of China's total agricultural greenhouse gas emissions that year. Correlation and regression analyses demonstrated that with increasing fertilizer application, crop production exhibits an inverted U-shaped growth trend, indicating limited effectiveness of high-intensity fertilizer use in increasing crop yields. These findings highlight the profound greenhouse effect resulting from the use of agricultural nitrogen fertilizer. Therefore, this study proposed technical and policy-level mitigation measures to address the issues caused by excessive fertilizer application, aiming to provide insights for controlling agricultural non-point source pollution and preserving the agroecological environment. [ABSTRACT FROM AUTHOR]

Precision fertilization is one of the key technologies to control non-point source pollution in agriculture. Fertilizer reduction and efficiency technology can greatly contribute to green and sustainable agriculture in the rice-oil rotation region in the mid-lower reaches of the Yangtze River. Among them, fertilizer apparatus s have been focused mainly on the performance and optimization of structural devices. It is relatively lacking in the high speed and precision of fertilizer apparatus for rapeseed in real time. It is a high demand to optimize the precision fertilizer discharging for the reference value. The performance of fertilizer apparatus can depend directly on the accuracy of working components, in terms of uniformity and rational fertilization. However, the existing fertilizer apparatus cannot fully meet the range of direct seeding rapeseed of high-speed machines, due to the jam, low stability and distribution, as well as the serious crushing of particle fertilizer. In this study, an extrusion fertilizer apparatus for rapeseed was designed with a centrifugal cavity disc with high speed and precision. According to the agronomic requirements of high-speed direct seeding, the movement analysis of fertilizer particles was combined to determine the key parameters, such as fertilizer inlet, centrifugal cavity disc, fertilizer outlet, and power system. The discrete element software (EDEM) was used to establish the simulation model of fertilizer discharging. A systematic investigation was implemented to clarify the influence of the speed of the fertilizer apparatus on the torque of the centrifugal cavity disc, the average load, and the crushing rate of fertilizer particles. The results showed that the torque of the centrifugal cavity disc increased, whereas, the average load of fertilizer particles in the cavity disk decreased gradually, and the crushing rate increased below 0.80%, with the increase of the speed of fertilizer apparatus. The performance test showed that the speed of the fertilizer ejector was 30-120 r/min, and the displacement was 15.0-58.1 g/s, fully meeting the demand of high-speed direct seeding when the maximum fertilization amount was 600 kg/hm2. The coefficient of variation was less than 8.58% for the consistent displacement in each row of fertilizer discharging, less than 6.45% for the stability of the displacement in the same industry, and the crushing rate was less than 0.89%; Specifically, the coefficient of variation was below 8.72% for the displacement consistency of each row shall under normal field operation with 0°~5° inclination. The comparative test showed that compared with the spiral perturbation, the fertilizer discharging with a centrifugal cavity disc was suitable for high-speed operation, where the crushing rate was reduced by 63.82%. There was no fertilizer jam when discharging fertilizer at high speed and large displacement. The field test showed that when the operation speed was in the range of 4.1-10.1 km/h, the coefficient of variation was not more than 6.72% for the consistent discharge in each row of the fertilizer ejector, while the coefficient of variation for the stability of the same row during fertilizer discharging was not more than 4.84%, and the relative error between actual and theoretical fertilizer discharging was less than 4.54%. The fertilizer discharging shared a wide range of displacement, smooth and stable operation, in order to effectively avoid the fertilizer sticking and the crushing rate in the process of fertilizer discharging. The fertilizer apparatus also fully met the demand for the high-speed direct seeding and precision fertilizer discharging of rapeseed. [ABSTRACT FROM AUTHOR]

The utilization of pesticides has experienced a substantial rise in order to enhance both the quantity and caliber of the produced goods. Agricultural runoff, a major source of nonpoint pollution, adversely impacts surface water, groundwater, soil and sediment quality in the watershed. Especially, organochlorine pesticides have adverse effects on the environment because of their toxicity, persistence and bioaccumulation. In this study, the presence of organochlorine pesticides (DDTs- dichlorodiphenyltrichloroethane and HCHs- hexachlorocyclohexane) in the environment of the dryland agricultural watershed, was determined. For this purpose, soil, sediment and water samples from the landscape of pond were collected. The concentrations of organochlorine pesticides in water, sediment, and soil ranged from 0.0005 to 0.0138 μg/L, 0.03 to 1.02 μg/kg, and 0.54 to 52 μg/kg, respectively. The persistence of these pesticides in soil and sediment poses long-term risks to both terrestrial and aquatic ecosystems. Sediment, as a significant reservoir for these contaminants, can act as a secondary source of pollution, releasing pesticides back into the water column under certain environmental conditions. Similarly, soil contamination not only affects plant health and productivity but also leads to further leaching and runoff into water bodies. The behavior of a toxic substance in water, soil and sediment environment, which is organochlorine pesticide, in a well-mixed lake watershed, was modeled using mass balances in the lake. Statistical analysis, including a paired t-test and calculation of the Nash-Sutcliffe index, confirms the consistency and reliability of the model’s predictions compared to observed data. Simulated concentrations closely matched observed values, and the distribution patterns and trends remained consistent across different months. Moreover, the Risk Quotient (RQ) for DDTs and HCHs is less than 0.1, indicating low ecological risk. [ABSTRACT FROM AUTHOR]

Globally, the concentration of heavy metals and sediment toxicity analysis are significant liabilities to aquatic environments. This scrutiny outlines the sediment textures, heavy metals and toxicity status associated with environmental pollution indices in the core sediment of the Cauvery and Vettar estuaries, East coast of India. The impact of rapid industrialization, urbanization, harbour activities and agricultural activities influences on the twain estuary is a significant concern to designate the environment. The contamination status of the sediments affects the potential biodiversity, ecological risks and human health. A total of two core sediments were recovered from the Cauvery and Vettar estuaries in March 2023 to decipher the environmental pollution status. Meticulous observation of the textural studies underscores the prevalence of sand content in Cauvery, and Vettar sediments consist of predominate clay content and minor silt contents. Furthermore, the organic matter is augmented in the Vettar River due to the higher input of waste disposal, seaweeds and algae due to the surrounding landmass. Twain core sediments argue that heavy metal concentration is decreasing in order as Fe > Zn > Ni > Pb > Cu > Cr by using portable X-ray fluorescence (pXRF) spectrometry. Remarkable results of environmental pollution indices such as Igeo, Ef, Cf, Cd and mCd state very highly polluted, extreme enrichments, high contamination and very high degree of contamination. Furthermore, the potential ecological risk indices such as PLI, SQGs, and PERI argue polluted, medium to high toxicity and moderate adverse ecological risk to the estuarine regions. Statistical analysis of the heavy metal affirms the enrichment of Fe metals may derive from lithogenic and/or anthropogenic influences, and the other studied metals such as Cu, Ni, Zn, Pb and Cr may be influenced by the anthropogenic activities in the aspect of point and non-point pollution sources. This could result from both estuaries undergoing higher pollution, in which the Vettar estuary is a considerable environmental risk zone compared to the Cauvery river due to the impact of industrial effluents and rapid urbanization activities. This finding underscores the urgent need for enhanced estuarine sediment quality study and comprehensive assessment of sediment toxicity, regulating the beneficial acumen for the government to follow the suitable remediation on the embellish policy of river and marine environments. [ABSTRACT FROM AUTHOR]

Nonpoint source pollution (NPS) has been known as runoff or diffuse pollution. It is still difficult to real-time monitor and simulate NPS, due to the significantly complex influencing factors. Therefore, the assessment theory of landscape ecological risk can be expected to identify the regional pollution risk from the perspective of landscape pattern and ecological process. In this study, NPS risk assessment was established using the “ source-sink“ landscape pattern theory. The first step was to identify “source-sink“ landscape. Cultivated, residential, transportation and commercial land were identified “ source landscape", while woodland, green land, water area and wetland were identified “sink“ landscape. The second step was the landscape spatial load comparison index (LCI) correction. The output coefficient and empirical model were combined to determine the “ source-sink” landscape pollutant output/interception coefficient. Then, the slope, altitude and distance from river were selected as the pollutions migration factors to correct LCI values. The final step was to evaluate the NPS pollution risk. The risk was calculated by LCI, slope factor and cost distance. The risks were divided into three grades, according to the natural breakpoint. Taking Shenzhen River-bay Basin as an example, the risk of NPS pollution was assessed using the “ source-sink“ landscape pattern theory. The numerical and spatial correlation analysis was conducted with the field monitoring pollutant data to verify the accuracy of the improved model. The research results showed that: (1) No.7, 9, 10, 12 and 13 watersheds were the high risk of NPS in Shenzhen River-Bay watershed in the whole Buji River basin and the lower reaches of Futian River basin. The low-risk areas were except No. 1 and 6 watersheds in the north of study area and No. 16, 17 and 18 watersheds in the east of study area. The rest 8 watersheds were all medium risk areas. NPS risk level was closely related to the “source-sink” landscape area ratio and landscape spatial pollutants load index, but the topographic factor shared the little influence on the basin. The residential land and transportation land showed the largest contribution rate to NPS risk, while the forest land and water area had outstanding effect on pollutant retention. (2) Both average concentrations of total nitrogen (TN) and total phosphorus (TP) in Shenzhen River-Bay basin were fully met the IV standard level of surface water quality. The average concentration exceedance rate of TN and TP were 12.99% and 11.89%, respectively, in rainy season, and 8.61% and 9.44% in the non-rainy reason. The maximum concentrations of pollutions occurred in the rainy season. The pollutants spatial analysis showed that Shenzhen River basin pollution risk was more serious than Shenzhen Bay basin, while the downstream was than in the upstream, and the higher in the coastal area than in the non-coastal area. The pollutants monitoring data showed that the high-risk area of NPS were No.5, 7, 9, 10, 12, 13 watersheds. Except No.5 watershed, the high-risk watersheds were consistent between monitoring and assessment. (3) The NPS risk assessment index using the “source-sink” landscape theory shared a significant correlation with the actual monitoring risk of TN and TP, indicating a highly spatial aggregation. The NPS risk assessment index can also provide the scientific and accurate reference to assess the ecological risk of watershed in regional scale. [ABSTRACT FROM AUTHOR]

Nonpoint source (NPS) pollution has emerged as the predominant water environment issue confronting plateau lakes in central Yunnan. Quantitative analysis of the impact of NPS pollution on water quality constitutes the key to preventing and controlling water pollution. However, currently, there is a dearth of research on identifying NPS pollution risks and exploring their relationship with water quality based on the Minimum Cumulative Resistance (MCR) model in the plateau lake basins of central Yunnan. Particularly, studies on the spatial heterogeneity of the impact of NPS pollution on water quality from a multi-scale perspective are scarce. Therefore, this study focuses on three typical lake basins in the Central Yunnan Plateau–Fuxian Lake, Xingyun Lake, and Qilu Lake (the Three Lakes). Utilizing the MCR model to identify NPS pollution risks, the study analyzes seven different scales, including sub-basins, riparian buffer zones (100 m, 300 m, 500 m, 700 m, and 1,000 m) and lakeshore zones, to reveal the multi-scale effects of NPS pollution on water quality through correlation analysis. The results indicate that: (1) Over 60% of the areas in the Three Lakes Basin are at high or extremely high risk, mainly concentrated in flat terrain and around inflow rivers; (2) The area of NPS pollution from paddy field source landscape (PFSL) is greater than that from construction land source landscape (CLSL), and the high-risk areas of NPS pollution are also larger for PFSL compared to CLSL; (3) The mean resistance values of PFSL and CLSL show a significant negative correlation with monthly mean values of water quality indexes (NH3-N, TP, CODCr), with the 1,000 m riparian buffer zone scale showing the greatest correlation with most water quality indexes, especially NH3-N; (4) The correlation between the mean resistance value of CLSL and the monthly mean values of water quality indexes is significantly higher than that of PFSL, indicating a greater impact of CLSL on water quality compared to PFSL. In summary, PFSL and CLSL are the primary sources of NPS pollution in the Three Lakes Basins. The 1,000 m riparian buffer zone scale is the most sensitive to the impact of NPS pollution on water quality. This study provides scientific references for landscape pattern optimization and precise control of NPS pollution risks in the Central Yunnan Plateau lake basins and offers a new research perspective for exploring multi-scale effects of NPS pollution on water quality. [ABSTRACT FROM AUTHOR]

Affected by point and non-point source pollution, the Fenhe River Basin faces significant environmental challenges. This study aimed to analyze the distribution characteristics and influencing factors of antibiotics in the water and sediments of the Fenhe River Basin. Samples were collected from 23 sites within the basin, and 26 antibiotics from five different classes were detected and analyzed using high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS). The water–sediment partition coefficient (Kp) was calculated, and spatial analysis was conducted using geographic information system (GIS) technology. The results showed that 25 antibiotics were detected in the water, with concentrations ranging from 130 to 1615 ng/L, and 17 antibiotics were detected in the sediments, with concentrations ranging from 121 to 426 μg/kg. For quinolones (QNs), except for ofloxacin, all others could be calculated with overall high values of Kp ranging from 692 to 16,106 L/kg. The Kp values for QNs were generally higher in the midstream, with considerable point source pollution from industries and non-point source pollution from developed agriculture. The distribution of Kp is closely associated with risk. This study found that the Kp values of the antibiotics were influenced by various factors such as temperature, water flow, and the physicochemical properties of sediments. Correlation analysis revealed significant relationships between Kp and parameters such as river width, water depth, water quality (total nitrogen, total phosphorus, and chemical oxygen demand), and sediment pH and clay content. [ABSTRACT FROM AUTHOR]

Agriculture continues to be one of the most important sources of nonpoint source pollution to surface water bodies. Consequently, it is critical to identify and prioritize high‐contributing agricultural fields and sub‐field areas for reducing soil erosion and sediment delivery by implementing best management practices (BMPs). Current erosion risk assessment tools are either complex modelling approaches or rely on a simplified reality and generalized assumption. The Daily Erosion Project (DEP) is a daily estimator of precipitation, hillslope runoff, detachment and soil loss covering ~630 000 km2 across the Midwest United States. These estimations are reported daily and publicly at the hydrologic unit code 12 watershed resolution (approximately 100 km2). The main objective of this study was to develop a new tool (named Overland Flow Element tool [OFEtool]) that downscales the watershed scale of DEP to estimate average runoff and soil displacement within a field, helping to locate erosive hotspots at multiple scales. We also demonstrated the applicability of OFEtool in Bennet Creek‐Sugar Creek in East Central Iowa (the United States) and compared its results with other erosion vulnerability tools such as the Soil Vulnerability Index for Cultivated Cropland (SVI‐cc) and a GIS‐based Revised Universal Soil Loss Equation (RUSLE). The same erosion risk classes and ranges (low, moderate, moderately high and high) were implemented for all indexes. The advantages of the OFEtool compared to the SVI‐cc and RUSLE models are related to the use of an event‐based modelling approach, such as DEP, with updated soil loss estimates based on temporal changes in climate inputs and land use and management. The OFEtool uses a 6‐year time frame and a more up‐to‐date field inputs, while RUSLE provides a long‐term average and SVI‐cc only considers soil and topographical factors for risk assessment. Results indicated that the spatial distribution of vulnerable fields (and parts of the fields) followed a similar trend as other tested indices. However, the risk level associated with each tool differed (SVI‐cc > RUSLE > OFEtool). These differences could arise from intrinsic disparities within the tools (inputs, timing, processes considered, assumptions). While currently limited to the DEP domain and relying on the DEP random sampling scheme, further research is warranted to validate the tool at other Midwest locations and ensure it captures the watershed's landscape variability (combination of terrain, soil, land use and management) required to identifying critical erosion hotspots. [ABSTRACT FROM AUTHOR]

Agricultural phosphorus (P) loss constitutes a significant factor in agricultural non-point source pollution (ANSP). Due to the widespread occurrence and complexity of ANSP, emphasis on risk prevention and control is preferable to retroactive treatment, to reduce costs. Effective risk identification is an issue that needs to be addressed urgently. Henan Province, a typical intensive agricultural region in China, was used as a case study to develop a straightforward and precise model for assessing the risk of P loss. Total phosphorus (TP) emission intensity at the county level in Henan Province was estimated based on planting, livestock and poultry breeding, and rural domestic activities. Subsequently, influential factors were selected to determine the extent of P loss in rivers. Finally, the model was validated using water quality data. The results indicate that (1) TP emission and rainfall are the primary contributors to the risk of P loss, whereas vegetation coverage has negligible effects. (2) The primary sources of TP emission, in descending order of magnitude, are livestock and poultry breeding, rural domestic activities, and planting. Livestock and poultry breeding represents the largest proportion at approximately 50%. (3) High-risk areas for P loss are concentrated in the plains of the central, eastern, and northern Henan Province, while low-risk areas are mainly located in the western mountainous and hilly regions. (4) The model exhibits high accuracy with a determination coefficient (R2) of 0.81 when compared to surface water quality monitoring data. This study provides a new framework for assessing the risk of P loss in intensive agricultural settings. [ABSTRACT FROM AUTHOR]

Non-point source pollution and water eutrophication from agricultural runoff present global challenges that impact ground and surface waters. The search for a feasible and sustainable mitigation strategy to combat this issue remains ongoing. This scoping review aims to explore one potential solution by examining relevant literature on agricultural practices of the past and recent edge-of-field measures, designed to ameliorate the impacts of agricultural runoff on soil and water quality. The study focuses on integrating findings from diverse research fields into a novel myco-phytoremediation approach, which involves the synergistic relationship of plants, arbuscular mycorrhizal fungi, and plant beneficial bacteria within vegetative buffer strips. The implementation of these augmented buffer strips enhances nutrient retention in the soil, reduces runoff volume, promotes biodiversity, and increases plant biomass. This biomass can be converted into biochar, an effective sorbent that can be used to filter dissolved and particulate nutrients from surface waterways. The resulting nutrient-rich biochar can be repurposed as a form of bio-fertiliser, optimizing fertiliser consumption and subsequently reducing the depletion rate of phosphorus, a limited resource. This paper investigates a circular model of abatement of agricultural runoff via maximal nutrient retention and subsequent recycling of nitrogen and phosphorus back into the agricultural system. The key impact lies in its contribution to addressing the issue of non-point source pollution and eutrophication by encouraging multidisciplinary research aimed at solving these complex environmental issues. [ABSTRACT FROM AUTHOR]

The acceleration of urbanization has disrupted natural water cycles, resulting in increased impervious urban surfaces and non-point source pollution from stormwater runoff. Addressing urban stormwater recharge has become crucial. This study introduces a novel silica sand-based permeable filtration material, investigating its surface characteristics, pore structure, permeability, and pollutant interception capabilities. The results demonstrate that hydrophilic binder coating modification of the permeable surface sand aggregate, combined with hydrophilic inorganic additives, having a porous structure with an average pore size of less than 50 μm and a porosity between 15% and 35%, significantly enhances surface hydrophilicity, achieving a permeation rate of up to 6.8 mL/(min·cm²). Moreover, it shows exceptional filtration and anti-clogging properties, achieving over 98% suspended solids interception and strong resistance to fouling. Dynamic biofilm formation experiments using simulated rain and domestic wastewater explore biofilm morphology and function on silica sand filtration well surfaces. Mature biofilms sustain COD removal efficiency exceeding 70%, with levels consistently below 50 mg/L, NH4+ decreasing to 2 mg N/L, and total nitrogen maintained below 10 mg N/L. The system features anoxic, anoxic, and aerobic zones, fostering synergistic organic matter and nitrogen removal by diverse microorganisms, enhancing pollutant mitigation. Silica sand-based permeable filtration material effectively mitigates urban stormwater runoff pollutants—suspended solids, organic matter, and nitrogen—offering an innovative solution for sponge city development and rainwater resource management. [ABSTRACT FROM AUTHOR]

We explored the risk level zoning and control measures for agricultural non-point source pollution, which used the equivalent standard pollution load method and GIS spatial analysis method to fully grasp the pollution situation in Hunan Province. Based on the equivalent pollution load of land area and the pollution load per unit of surface runoff, this paper analyzed the data of the sources, types, and spatial distribution of agricultural non-point pollution sources in Hunan Province from 2018 to 2021. The results showed that the TN pollution load of agricultural non-point sources was the highest, with the contribution rate more than 40% from 2018 to 2020. The value was generally higher at the center of the province and gradually decreased in the surrounding area. The risk level of Hunan Province can be zoned into three levels, i. e., high-risk areas, medium-risk areas, and low-risk areas, via natural discontinuity grading method. The pollution sources can be divided into six types, i.e., livestock and poultry farming pollution type, rural domestic sewage pollution type, rural domestic sewage livestock and poultry breeding pollution type, rural domestic sewage planting pollution type, planting livestock and poultry breeding pollution type, and combined pollution type. The control measures of agricultural non-point source pollution in Hunan Province were put forward according to 14 sub-regions based on the above six source types. [ABSTRACT FROM AUTHOR]

Objectives: With the rejuvenated emphasis on nonpoint pollution under the Water Quality Act (WQA) of 1987, Environmental Protection Agency (EPA) began to face an onslaught of lawsuits designed to pressure the EPA to enforce the requirements of Section 319 of the WQA to address nonpoint pollution. Known as Total Maximum Daily Load (TMDL) agreements, the purpose of these plans was to limit the amount of polluted runoff reaching a state's waterways. While some states took a proactive stance on these plans, other states resisted the implementation of Section 319. This article seeks to understand state choices in the development and implementation of TMDL agreements. Methods: Utilizing a data set spanning state‐level data from 2000 to 2020, we test a novel cross‐sectional time series model employing the number agreements entered into by a state as the dependent variable. Results: We find that both political and need explanations are generally supported, while policy need explanations are somewhat more promising. Conclusions: Taken together, the models offer several insights into state choices around TMDL creation. The political model is the weakest, suggesting that TMDLs are not overtly political. Policy needs seem to play a more critical role in the preponderance of TMDL agreements than partisan politics. [ABSTRACT FROM AUTHOR]

Excessive fertilizer application increases the risk of eutrophication and agricultural non-point source pollution (ANPS) in rivers near farmland. However, the processes and mechanisms of runoff and phosphorus losses, particularly in the interflow, under various fertilizer treatments and rainfall scenarios are not well understood. This study used orthogonal experimental methods to investigate the combined effects of fertilization schemes and rainfall intensity on multi-form phosphorus runoff losses and to establish statistical relationships and regression models between phosphorus losses and environmental factors in surface runoff and interflow. The results indicated that (1) the optimized fertilization scheme, compared with conventional fertilization, enhanced pak choi (Brassica rapa) growth while reducing phosphorus runoff losses. By reducing phosphorus fertilization by 35.7%, total phosphorus losses decreased by 29.3%, 34.2%, and 29.8% under light, moderate, and heavy rainfall, respectively. (2) Different fertilizer applications and rainfall intensities had varying effects on phosphorus losses through different pathways. Fertilizer application was the primary factor affecting phosphorus losses in surface runoff, while rainfall intensity mainly influenced phosphorus losses through interflow. (3) Surface runoff was the dominant pathway for phosphorus losses from farmland (>92.0%), with particulate phosphorus (>89.4%) being the predominant form. However, under high-intensity and long-duration rainfall, interflow became a significant pathway for phosphorus losses. This study highlights the importance of optimized fertilization in reducing phosphorus losses and improving fertilizer efficiency in agricultural fields. The findings will help develop strategies to mitigate ANPS and soil nutrient losses in the North China Plain. [ABSTRACT FROM AUTHOR]

Because of its low‐lying location, urbanization, and inadequate infrastructure, Jakarta (Indonesia) has experienced an increase in annual flooding events, rising from an average of five significant floods per year in the 1990s to over 20 annually (2010–2020). With climate change exacerbating extreme weather events, Jakarta encounters escalating risks of flooding. Although the recurrent flooding is exacerbated by non‐point source (NPS) of pollution such as urban runoff and agricultural discharge that contribute to 40% of total pollutants leading to flood‐related issues in Jakarta, none has investigated this research gap. To reflect its novelty, this work explores the implications of climate change on the annual flooding in Jakarta by focusing on NPS and analyzes their impacts from social perspectives. This work also underscores the implications of flooding on livelihoods, health, and social cohesion in Jakarta. Focus group discussion with affected residents was used to shed light on the coping strategies employed in response to recurrent floods, ranging from community‐based initiatives to reliance on informal networks. The empirical findings show that the implications of flooding extend beyond physical damages. Displacement of communities, loss of livelihoods, disruption of essential services, and increased health risks are among the social impacts experienced by local residents. Vulnerable populations, including low‐income communities residing in informal settlements, bear their consequences. Economic losses from flooding amount to USD 500 million annually, impacting over 1 million residents. However, recent interventions have led to a 15% reduction in peak flood levels and a 20% reduction in flood duration in affected areas. Community resilience has also improved, with a 25% increase in flood insurance coverage and a 20% rise in community response initiatives. Overall, this study highlights that climate change exacerbates annual flooding in Jakarta, significantly impacting vulnerable communities through NPS pollution. Addressing the challenges requires integrated approaches combining effective pollution control, resilient infrastructure, and community engagement to mitigate social and long‐term environmental impacts. Practitioner Points: Climate‐induced flooding disproportionately affects vulnerable communities in Jakarta.Non‐point source pollution from urban runoff contributes to the severity of flooding in Jakarta.Waterborne diseases, disruption of livelihoods, and reduced access to clean water are major concerns identified in the study.The study highlights the importance of community‐based adaptation strategies to mitigate the impact of flooding and pollution. [ABSTRACT FROM AUTHOR]

China's unsustainable agricultural production activities have caused severe agricultural non-point source pollution (ANPSP), particularly nitrogen source pollution (NSP), which impacts farmland ecological environments. Understanding NSP is important for managing ANPSP and improving environmental water quality. Thus, inventory analysis methods were used to assess county-level total nitrogen (TN) loads in large-scale agricultural areas, analyze spatial and temporal variations in TN loads, examine the major sources of TN loads and identify the driving factors of DITN using Pearson correlation and random forest (RF) methods. The results showed that (1) TN loads and discharge intensity decreased by 4.59% and 12.7%, respectively, increasing and then decreasing via market regulations, policy incentives, and policy constraints. The eastern and northern Henan Province plain areas were highly discharged. (2) The major pollution sources varied, with the total contributions of mineral fertilizers and livestock and poultry breeding to TN being 73.53% and 81.78%, respectively. Farmland solid waste contributed minimally but increased yearly from 10.84 to 19.74%. (3) The discharge intensity of TN was highly significantly negatively correlated with the urbanization rate, economic development and slope; neither was significantly correlated with arable land. The RF results showed that total mineral fertilizer consumption and total livestock and poultry production were the major factors controlling the NSP in Henan Province. China's agricultural policies have slightly reduced pollutant discharge intensities, but the situation remains grim. This study provides a scientific basis for the development of differentiated TN control measures in Henan Province, which is important for improving pollution prevention and control capabilities. [ABSTRACT FROM AUTHOR]

Water quality impairment from fertilizer runoff remains a major source of urban-agricultural conflicts when it leads to serious health risks. In this paper, we analyze the role of watershed organizations in Iowa, USA, that include both agricultural and urban stakeholders to address water quality challenges. We conducted three focus group discussions with 14 coordinators representing these watershed organizations to analyze what policy tools these organizations are using to address urban-agricultural conflicts and what outcomes have resulted from their efforts. We used qualitative coding to apply an existing set of policy tools already established in the literature. Coordinators' responses showed that who participates in these organizations has a major impact on the level of problem solving. There were limited instances of joint urban-agricultural engagement strategies, but these were promising in changing individual's perspectives and indicate that strategic targeting of watershed participants may be crucial to overcoming conflicts. [ABSTRACT FROM AUTHOR]

Water quality monitoring is imperative in providing the objective evidence required to make sound decisions about water quality management. This study aimed to examine the water quality status of the Migori River by determining spatio-seasonal variations in water quality parameters, along with associated influencing factors and potential health risks. Therefore, eighteen physico-chemical and bacteriological variables were sampled and analyzed monthly for six months covering the wet and dry seasons from the upstream, midstream, and downstream stations, and a health risk survey was conducted with 90 watershed households. ANOVA and T-test were used to test for the significant spatial and seasonal variations (p < 0.05), respectively; whereas Pearson's correlation was used to identify relationships between parameters. Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) were used to find various spatial patterns in the river water quality datasets, while the Canadian Council of Ministries of the Environment Water Quality Index (CCME-WQI) showed the suitability status of the river water quality. The assessed variables showed significant seasonal variability but no significant spatial differences in the river. HCA generated 3 clusters suggesting that water quality deteriorated downstream from the upstream of the watershed. The PCA extracted four PCs explaining 80.5% of the total variance, which suggested that the variations in water quality are attributed to point and nonpoint sources of pollution. While most of the physico-chemical variables were within maximum permissible limits, the bacteriological levels exceeded the prescribed standards. The index ranked the river's water condition between 'poor' to 'marginal'; upstream has better water condition that gradually decreases toward the downstream, and water quality is better in the wet season than the dry season. The study revealed that the water of the Migori River is polluted and potentially hazardous for human usage, and thus suitable pollution control measures are urgently needed to safeguard public health. [ABSTRACT FROM AUTHOR]

In order to address the increasingly prominent issues of water resource protection and agricultural non-point source pollution in the Erhai Lake Basin, this study conducted a two-year field experiment in Gusheng Village, located in the Erhai Lake Basin. In 2022, two irrigation treatments were set up: conventional flooding irrigation (CK) and controlled irrigation (C), with three replicates for each treatment. In 2023, aiming to enhance the utilization rate of rainwater resources and reduce the direct discharge of dry-farming tailwater from upstream into Erhai Lake. The paddy field was used as an ecological storage basin, and the water storage depth of the paddy field was increased compared to the depth of 2022. Combined with the deep storage of rainwater, the dry-farming tailwater was recharged into the paddy field to reduce the drainage. In 2023, two water treatments, flooding irrigation with deep storage and controlled drainage (CKCD) and water-saving irrigation with deep storage and controlled drainage (CCD) were set up, and each treatment was set up with three replicates. The growth and physiological index of rice at various stages were observed. Nitrogen leaching of paddy field in surface water, soil water, and groundwater under different water treatments after tillering fertilizer were observed. The research results show that the combined application of organic and inorganic fertilizers under organic planting can provide more reasonable nutrient supply for rice, promote dry matter accumulation and other indices, and also reduce the concentration of NH4+-N in surface water. Compared with CK, the yield, 1000-grain weight, root-to-shoot ratio, and leaf area index of C are increased by 4.8%, 4.1%, 20.9%, and 9.7%, respectively. Compared with CKCD, the yield, 1000-grain weight, root-to-shoot ratio, and leaf area index of CCD are increased by 6.5%, 3.8%, 19.6%, and 21.9%, respectively. The yield in 2023 is 19% higher than that in 2022. Treatment C can increase the growth indicators and reduce the net photosynthetic rate to a certain extent, while CCD rain-flood storage can alleviate the inhibition of low irrigation lower limit on the net photosynthetic rate of rice. Both C and CCD can reduce nitrogen loss and irrigation amount in paddy fields. CCD can reduce the tailwater in the Gusheng area of the Erhai Lake Basin to Erhai Lake, and also can make full use of N, P, and other nutrients in the tailwater to promote the formation and development of rice. In conclusion, the paddy field rain-flood storage methodology in the Erhai Lake Basin can promote various growth and physiological indicators of rice, improve water resource utilization efficiency, reduce direct discharge of tailwater into Erhai Lake, and decrease the risk of agricultural non-point source pollution. [ABSTRACT FROM AUTHOR]

Water security, as a crucial component of national security, plays a significant role in maintaining regional stability and ensuring the healthy and rapid development of the economy and society. The Yellow River water-receiving area of Henan Province (YRWAR-HN) is selected as the research area in this study. Firstly, a comprehensive evaluation index system is constructed based on the actual water security problems of the research area, and the single index quantification–multiple indices syntheses–poly-criteria integration method (SMI-P) is introduced to quantify the water security degree of 14 cities in the YRWAR-HN from 2010 to 2021. Then, the obstacle degree model is used to identify the key obstacle indexes that restrict the improvement of water security. Finally, the harmonious behavior set optimization method is adopted to carry out the regulation of water security, and the improvement path of water security in the YRWAR-HN is formulated. The results indicate the following: (1) the water security degree of the YRWAR-HN shows a fluctuating upward trend, increasing from 0.4348 (2010) to 0.6766 (2021), a significant rise of 55.61%. The water security level improves from the relatively unsafe level to the relatively safe level. Hebi City exhibits the fastest rate of water security improvement, while Xinxiang City shows the slowest rate. (2) The density of the river network (X1) and the proportion of investment in water conservancy and environmental protection in the total investment (X15) are the two indexes with the highest obstacle degree, with the average obstacle degrees being 15.09% and 10.79%, respectively. (3) The combination of the composite regulation scenario and improvement Path 2 is the optimal regulation strategy for water security in the YRWAR-HN. From the implementation process, Luoyang, Sanmenxia, Jiyuan, Xuchang, and Shangqiu may prioritize improving their flood and drought disaster defense capabilities and emergency response capabilities, continuously enhancing the flood prevention and disaster reduction system. Zhengzhou, Kaifeng, Xinxiang, Jiaozuo, Anyang, Hebi, Pingdingshan, and Zhoukou may prioritize resolving the regional water supply and demand conflicts, balancing development and conservation, actively seeking transboundary and external water transfers, and strengthening the capacity for water conservation and intensive utilization. Puyang City may prioritize enhancing its comprehensive water environment management capabilities, increasing investment in water conservancy and the environment, improving production processes, reducing pollutant emissions, and mitigating agricultural non-point source pollution. [ABSTRACT FROM AUTHOR]

Changes in land use and landscape patterns significantly influence watershed water quality by affecting non-point source (NPS) pollution processes. Understanding the characteristics of water quality and the relationships between landscape patterns and water quality is crucial to informing land-use planning aimed at ensuring water security. In this study, we employed landscape index methods, correlation analysis, and redundancy analysis based on monitored water quality data and land-use types relative to the Yanshan River Basin, Guilin, China. The results show the following features: (1) Water quality in the small watershed exceeded the values of class III during the study period, and total nitrogen (TN) was the main pollutant, with a pollution load ratio reaching 67.9%. (2) Water quality was significantly impacted by the landscape patterns of the small watershed river. The monitored concentrations of TN, ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3−-N), and total phosphorus (TP) were negatively correlated with the proportion of forest area, and the concentrations of NH4+-N and TP were positively correlated with the proportions of building, orchard, and cultivated land areas. Moreover, the influences of landscape patterns during the wet seasons on water quality were stronger than those during the dry seasons. (3) The total interpretation rates of the landscape indices for the water quality indices in the dry and wet seasons were 96.7% and 94.4%, respectively. Moreover, the largest patch and aggregation indices of the building area were the most effective variables in explaining the water quality indices, with contribution rates of 30.8% and 23.2% in the dry seasons and 34.3% and 23.8% in the wet seasons, respectively. By analyzing these relationships, in this study, we obtained insights into how different landscape patterns contribute to variations in water quality. The findings contribute to sustainable land-use planning strategies that aim to mitigate the impacts of land-use changes on water resources. [ABSTRACT FROM AUTHOR]

This study evaluates the impact of green finance on agricultural non-point source pollution control and emission reduction in 30 Chinese provinces from 2005 to 2022. Utilizing the entropy value method and the unit survey inventory method, the research measures the levels of green finance development and agricultural non-point source pollution. It employs a mediation effect model to empirically assess the pollution control efficacy of green finance and to elucidate the mechanisms underlying its influence. The findings indicate that green finance development significantly curtails agricultural non-point source pollution emissions. This conclusion is still valid after a series of robustness tests. The results of mechanism analysis show that environmental regulation and land transfer are important channels for green finance to reduce agricultural non-point source pollution. However, the slowing effect of green finance is stronger in provinces where the economic development level is still in the catch-up zone. Consequently, this study suggests strengthening green finance infrastructure in rural areas, coordinating green finance and environmental regulation policies, optimizing land transfer systems to promote scale management, and developing differentiated green finance policies based on regional economic development levels. These measures aim to augment the role of green finance in pollution treatment and emission reduction, thereby optimizing the green financial system, advancing environmental protection, and fostering sustainable development in China's agricultural sector. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Northwest A & F University - Natural Science Edition is the property of Editorial Department of Journal of Northwest A&F University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Vegetable runoff nitrogen (N) loss is a serious environmental issue. However, whether the volume or N content of runoff determines the final N losses has not been clarified, which limited the optimal N managements in vegetable production. Here, we conducted a simulated rainfall experiment to study the runoff N loss flux pattern and the accumulation rate as well as the main influencing factors. The results showed that at 20 to 30 min, the volume of runoff water with a high N content reaches a critical inflection point of increase. Under 55 mm/h rainfall intensity, the N concentration decreased continuously. Under 75 mm/h, the soluble N concentration decreased during the first 25 min; thereafter, it stabilized. However, the total and particulate N decreased significantly after 30 min. Nitrogen losses via runoff from vegetable fields were from 18.5 to 26.0 kg/ha under two rainfall intensities. Runoff soluble N losses were mainly attributed to applied fertilizers (79.7%–95.5%), while particulate N losses were primarily originated from soil-retained N. Our data indicates that there was a significant difference in N losses pattern and influencing factors under varied fertilizer N inputs and rainfall intensities, which can help to optimize water and N fertilizer managements to mitigate non-point source N pollutants. In the future, long-term multi-site and -crop studies should be conducted to comprehensively clarify the N runoff losses in vegetable soils. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The landscape pattern controls the energy flow and water sediment process of the watershed, which is an important factor affecting nitrogen and phosphorus loss in small watershed. In order to understand the responses of rainfall-runoff processes and nitrogen and phosphorus exports to landscape pattern, two typical small watersheds, Shuangxi (agroforestry catchment) and Shiqiao (forest catchment) in the upper watershed of Liangzi Lake area of Hubei Province, were selected as the research objects. The water quality and quantity at the outlet of the watersheds were continuously monitored from January to December and a secondary rainfall event in 2016. The results showed that the landscape patterns had a significant impact on responses of rainfall-runoff processes. Compared with Shuangxi, the runoff process in Shiqiao small watershed showed a trend of shorter convergence time, faster runoff response speed and larger runoff modulus. The monthly concentrations of total nitrogen (TN) and total phosphorus (TP) in Shuangxi small watershed were in the range of 1.29~4.28 mg/L and 0.04~0.22 mg/L, which were higher than those of Shiqiao (TN:0.62~1.90 mg/L; TP:0.02~0.11 mg/L), respectively. Nitrate nitrogen (NO-³-N) was the major form of TN in the two small catchments, accounted for 51.8%~88.2%, but the proportion of NO-³-N to TN in Shuangxi small watershed was higher than those of Shiqiao. The concentrations of ammonium (NH+4-N) and nitrite nitrogen (NO-²-N) remained at a low level and exhibited no obvious trend. The emission fluxes of TN and TP in Shuangxi small watershed were in the range of 1.83~20.03 g/s and 0.04~1.45 g/s,which were higher than those of Shiqiao (TN:0.62~10.01 g/s; TP:0.01~0.54g/s), respectively. It was also found that there was a significant positive correlation between the TN and TP emission flux and runoff in the same period. The annual loss intensity of TN and TP in Shuangxi small watershed were 3.68 t/(km² · a) and 0.20 t/(km² · a), which were 1.32 and 1.30 times greater than those of Shiqiao, respectively. The losses of TN and TP in both small watersheds mainly occurred between April and July with frequent rainfall events, accounting for more than 70% of the annual total losses. In conclusion, different landscape patterns had a significant impact on the losses of TN and TP. Accordinglly, rational fertilization to reduce anthropogenic nitrogen and phosphorus loss and optimization of land use to store water and preserve soil are scientific measures to improve the water environment in the watershed. The study could provide more insights for reducing agricultural non-point source pollution in Liangzi Lake region and similar other regions. [ABSTRACT FROM AUTHOR]

Rapid socio-economic development has led to many water environmental issues in small watersheds such as non-compliance with water quality standards, complex pollution sources, and difficulties in water environment management. To achieve a quantitative evaluation of water quality, identify pollution sources, and implement refined management in small watersheds, this study collected monthly seven water quality indexes of four monitoring points from 2010 to 2023, and ten water quality indexes of 23 sampling points in the Shiting River and Mianyuan River which are tributaries of the Tuojiang River Basin. Then, water quality evaluation and pollution source analysis were conducted from both temporal and spatial perspectives using the Water Quality Index (WQI) method, the Absolute Principal Component Scores/Multiple Linear Regression (APCS-MLR) method, and the Positive Matrix Factorization (PMF) receptor modeling technique. The results indicated that except for total nitrogen (TN), the concentrations of other water quality indexes exhibited a decreasing trend, and all were divided into two obvious stages before and after 2016. Furthermore, the proportion of water quality grade of Good and above increased from 73.96 to 84.94% from 2010–2015 to 2016–2023, and the water quality grade of Good and above from upstream to downstream dropped from 100 to 23.33%. From the temporal scale, four and five pollution sources were identified in the first and second stages, respectively. The distinct TN pollutant is mainly affected by agricultural non-point sources (NPS), whose impact is enhanced from 17.76 to 78.31%. Total phosphorus (TP) was affected by the phosphorus chemical industry, whose contribution gradually weakened from 50.8 to 24.9%. From a spatial perspective, four and five pollution sources were identified in the upstream and downstream, respectively. Therefore, even though there are some limitations due to the data availability of water monitory and hydrology data, the proposed research framework of this study can be applied to the water environmental management of other similar watersheds. [ABSTRACT FROM AUTHOR]

High-quality development of water resources supports high-quality socio-economic development. High-quality development connects high-quality life, and clarifying the key management contents of small watersheds plays an important role in building ecologically clean small watersheds and promoting regional production and life. Previous research on pollution loads has focused on examining the impact of various external drivers on pollution loads but still lacks research on the impact of changes in pollution sources themselves on pollution loads. In this study, sensitivity analysis was used to determine the impact of changes from different sources on the total pollution loads, which can recognize the critical pollution sources. We first employed the pollutant discharge coefficient method to quantify non-point source pollution loads in the small watershed in the upstream Tuojiang River basin from 2010 to 2021. Then, combination sensitivity analysis with Getis-Ord Gi* was used to identify the critical sources and their crucial areas at the global, districts (counties), and towns (streets) scales, respectively. The results indicate: (1) The pollution loads of COD, NH3-N, TN, and TP all show a decreasing trend, reducing by 18.3%, 16.2%, 18.6%, and 28.1% from 2010 to 2021, respectively; (2) Livestock and poultry breeding pollution source is the most critical source for majority areas across watershed; (3) High-risk areas are mainly concentrated in Jingyang district and its subordinate towns (streets). There is a trend of low-pollution risk areas transitioning to high-pollution risk areas, with high-risk areas predominantly concentrated in the southeast and exhibiting a noticeable phenomenon of pollution load spilling around. This study can promote other similar small watersheds, holding significant importance for non-point source pollution control in small watersheds. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Resources & Ecology is the property of Journal of Resources & Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• A coupled metal and metalloid transport model were developed based on improved two-dimensional hydrodynamic water quality model and SWAT model. • The contents and spatial-temporal distribution of arsenic were characterized. • Impacts of hydro-climate, hydropower station and non-point source were explored. • Model helps to quantify and analysis the transport of metalloid pollution. With the increasing severity of arsenic (As) pollution, quantifying the environmental behavior of pollutant based on numerical model has become an important approach to determine the potential impacts and finalize the precise control strategies. Taking the industrial-intensive Jinsha River Basin as typical area, a two-dimensional hydrodynamic water quality model coupled with Soil and Water Assessment Tool (SWAT) model was developed to accurately simulate the watershed-scale distribution and transport of As in the terrestrial and aquatic environment at high spatial and temporal resolution. The effects of hydro-climate change, hydropower station construction and non-point source emissions on As were quantified based on the coupled model. The result indicated that higher As concentration areas mainly centralized in urban districts and concentration slowly decreased from upstream to downstream. Due to the enhanced rainfall, the As concentration was significantly higher during the rainy season than the dry season. Hydro-climate change and the construction of hydropower station not only affected the dissolved As concentration, but also affected the adsorption and desorption of As in sediment. Furthermore, As concentration increased with the input of non-point source pollution, with the maximum increase about 30%, resulting that non-point sources contributed important pollutant impacts to waterways. The coupled model used in pollutant behavior analysis is general with high potential application to predict and mitigate water pollution. [Display omitted] [ABSTRACT FROM AUTHOR]

This study investigates the presence of new psychoactive substances (NPS) and their metabolites in two wastewater treatment plants (WWTPs) situated in South Wales, UK (WWTP-1 and WWTP-2). Analysis was conducted for 35 NPS and metabolites, along with the inclusion of benzoylecgonine (main cocaine metabolite) and cannabis, the most detected illicit substances. Benzoylecgonine was identified as the predominant substance in both WWTPs. Epidemiological calculations revealed the average population consumption of cocaine to be 3.88 mg/d/1000 inhabitants around WWTP-1 and 1.97 mg/d/1000 inhabitants for WWTP-2. The removal efficiency of benzoylecgonine across both WWTPs was observed at an average of 73%. Subsequent qualitative analyses on randomly selected wastewater samples detected medicinal compounds including buprenorphine, methadone, and codeine in both WWTPs. An additional experiment employing enzymatic hydrolysis revealed the presence of morphine, an increased presence of codeine, and 11-Nor-9-Carboxy-THC (THC-COOH) post-hydrolysis. These findings underscore the significant presence of illicit substances and medicinal compounds in wastewater systems with the absence of NPS within the South Wales area, highlighting the necessity for enhanced monitoring and treatment strategies to address public health and environmental concerns. [ABSTRACT FROM AUTHOR]

The Regional Pest Control program represents a strategic intervention aimed at optimizing pesticide use in crop production, thereby mitigating the environmental impact of agricultural non-point source pollution from pesticides and fostering the development of high-quality agriculture. This study examines the influence of farmers' perceived risks on the adoption of the Regional Pest Control program and evaluates its effect on pesticide application across a nationally representative dataset from Heilongjiang, Jiangsu, Anhui, Hubei, and Sichuan provinces. To account for unobserved heterogeneity, an endogenous switching regression model was employed. The findings reveal that farmers' perceived risks associated with the Regional Pest Control program significantly deter its adoption. Furthermore, the program has been effective not only in reducing the frequency of pesticide applications but also in increasing the usage of pesticides with lower acute toxicity levels. Notably, the impact of the Regional Pest Control program on pesticide application demonstrates considerable variation in accordance with farmers' risk attitudes. [ABSTRACT FROM AUTHOR]

Agricultural non-point source pollution (ANP) had become an important source of water pollution, which seriously restricted the coordinated development of Beijing, Tianjin and Hebei. As the primary agricultural production base in the region of Beijing-Tianjin-Hebei, Hebei had serious ANP. In order to clarify the current status of ANP in Hebei and figure out the main pollution source and areas, ANP load of Hebei from 2000 to 2021 were evaluated by the export coefficient modeling (ECM) and spatial-temporal characteristics were carried out using geographic information system (GIS). In addition, ANP severity and emission characteristics of Hebei in 2021 were evaluated. The results showed that the environmental impact of ANP in southwest area was obviously more serious than that in northeast area of Hebei. Especially, ANP emissions in Hebei showed significant decreasing inflection points in 2007 and 2017, respectively, reaching a minimum by 2021. The TN and TP emissions of ANP in Hebei were 315,026.1 t and 50,323.76 t in 2021, respectively. The contribution of agricultural land, livestock and poultry breeding and rural life to TN and TP emissions were 37%, 34%, 29% and 20%, 61% and 18%, respectively. The ANP pollution mainly came from livestock and poultry breeding in Hebei Province. Based on cluster analysis, cities in Hebei were divided into four types, and the control strategies for ANP environment management were put forward. [ABSTRACT FROM AUTHOR]

The safety of the source of drinking water is important to human health, and monitoring the occurrence of contamination, particularly antibiotics and toxic organic compounds, is critically essential. Such information also helps in managing and improving water quality. However, the degree and details of this contamination in drinking water sources of Guangdong province are still not clear. This study determined the residues of antibiotics and bisphenol compounds (BPs) in three water sources, including two reservoirs and one river, in Guangdong province, aiming to evaluate the drinking water safety and health risk. The results showed that a total of 32 antibiotics and 3 BPs (BPAF, BPs, BPA) were detected in March. The total concentration antibiotics and BPs ranged from not detected (nd) to 243.65 ng/L and nd to 7.47 ng/L, respectively. In August, a total of 35 antibiotics and 3 BPs (BPAF, BPS, BPA) were detected. The total concentrations of antibiotics and BPs ranged from 0.11 to 1793.72 ng/L and nd to 59.15 ng/L, respectively. The concentration of pollutants in August (wet season) was significantly higher than that in March (dry season). Principal component analysis showed that non-point source pollution concentrations increased in river-type water sources. The concentration of pollutants was generally higher in river water than in reservoir water. In addition, seasonal variations were observed. Health risk assessments for antibiotics indicate that chlortetracycline and oxytetracycline pose risks to the 0–3 month and 3–4 year age groups. The results of the ecological risk assessment revealed that in March and August, sulfamethoxazole, tetracycline, clarithromycin, lincomycin, roxithromycin, oxytetracycline, and enoxacin posed moderate or high risks. BPS posed a moderate risk at all sampling sites, while BPA presented a high risk. This study reveals the contamination problems of drinking water sources and provides the basis for the pollution control of water in Guangdong Province. [ABSTRACT FROM AUTHOR]

Wetlands are critical ecological infrastructures that improve water quality, serve as habitat for fish and other aquatic life, accumulate floodwaters, and maintain surface water flow during dry periods. However, the health of wetlands has been compromised by anthropogenic activities that affect the constant supply of ecosystem services. This study assessed the impact of anthropogenically modified land use on wetland health in the Witbank Dam Catchment in South Africa, whose land use has been severely modified for agriculture and mining purposes. The study developed a model linking surface runoff generated in the catchment with land use and wetland typology to comprehend diffuse pollution from pollution-source land uses. Runoff data and related wetland spatial information were processed and analysed in a Geographic Information System (GIS) to estimate pollutants (agricultural nutrients and acid mine drainage) from runoff detained and released by wetlands. The analysis facilitated the assessment of the value of wetlands in enhancing water quality, as well as human and environmental health. The runoff volume from pollution-source land uses (urban areas, farmlands, and mining) was used to evaluate annual pollution levels. Wetland types are ranked according to their efficiency levels to filter pollutants. The assumption is that the difference between filtered and unfiltered runoff is the quantity of polluted runoff water discharged into the river system. The analysis has shown that 85% of polluted runoff generated in the catchment ends up in the river system. An important observation is that although wetlands have a substantial ability to absorb excess pollutants, they have finite boundaries. Once they reach their full holding capacity, they can no longer absorb any further pollutants. The excess is discharged into the river system, risking human and environmental health. This explains why the Limpopo River is heavily polluted resulting in the death of fish, crocodiles and other aquatic life. [ABSTRACT FROM AUTHOR]

This study summarized and evaluated the cost-benefit analysis methods for typical water environment pollution control measures in China. We conducted a comprehensive comparison of these measures, whose advantages and disadvantages were examined, so the application models and characteristics can be delved into. Through integrating methods and analyzing application cases, we refined a combination of measures with high efficiency and low cost in controlling China's water environment. In our analysis of cost-benefit, we emphasized the importance of implementing scientifically designed control measures and employing rigorous methods to addressing water environment pollution. In order to achieve rapid response and efficient treatment of China's environmental problems, we advocated for establishing a cross regional pollution control mechanism. That is, the collaborative platform and scientific suggestions for all participants in this field should be provided, through interdisciplinary integration, development of domestic models, and expansion of databases. [ABSTRACT FROM AUTHOR]

The issue of agricultural non-point source pollution has attracted global attention. A buffer zone is an effective, eco-friendly, and economically feasible remediation ecosystem to reduce the impact of agricultural non-point source pollution on water bodies. They can effectively remove pollutants in agricultural drainage through physical processes (infiltration, filtration, deposition, etc.), plant absorption and assimilation, and microbial processes, improving the water quality of water bodies. This article provides a comprehensive review of the current studies on using buffer zones to remediate agricultural non-point source pollution, with a focus on the key affecting factors for pollutant removal efficiencies. The main factors included buffer zone width, vegetation type, slope, seasonal variation, soil variation, and vegetation density. The influencing mechanisms of these factors on the pollutant removal efficiencies of buffer zones were also discussed. This review can serve as a reference for a deep understanding of buffer zones and help optimize their design and management in real ecological remediation projects. [ABSTRACT FROM AUTHOR]

Controlling non-point source (NPS) pollution is crucial for implementing water environment management, and simulating the water quality response to NPS pollution emission control schemes is of great importance. Variational mode decomposition (VMD) can overcome endpoint effects and modal aliasing issues, effectively separating intrinsic mode components. Bidirectional long short-term memory (BiLSTM) can fully mine the information contained in time series and has good predictive performance. MIKE21, when coupled with the Ecolab module, can well simulate the diffusion process of NPS pollution. The Weihe River water environment prediction model was constructed using VMD-BiLSTM and MIKE21, with ammonia nitrogen (NH3-N), total phosphorus (TP), and chemical oxygen demand (COD) as pollution indicators, showing the water quality response of the Weihe River within a few years after the implementation of agricultural and urban NPS pollution emission control schemes. Among them, the COD concentration decreased by up to 71.3%, the NH3-N concentration decreased by up to 31.4%, and the TP concentration decreased by up to 43.1%. In the process of streamflow prediction, VMD-BiSLTM shows satisfactory performance with NSE of 0.89 and R2 of 0.92, which will significantly improve the accuracy of modeling the future water environment. The results also show that the water quality of the Weihe River can be significantly improved by controlling NPS pollution emission, and reducing agricultural NPS pollution emission is key to decreasing ammonia nitrogen and total phosphorus concentrations and improving water quality. [ABSTRACT FROM AUTHOR]

The medium-intensity karst desertification environment is typically characterized by more rocks and less soil. The abandoned land in the construction areas of the dry-hot river valley hydropower station has more infertile soil, severe land degradation, and very low land productivity. Therefore, it is urgent to improve the soil quality to curb the increasingly degrading land and reuse the construction site. Few studies have focused on the effect of soil restoration and comprehensive evaluation of soil quality with multi-treatment in abandoned land in the dry-hot valley hydropower station construction area. Here, 9 soil restoration measures and 1 control group were installed at the Guangzhao Hydropower Station construction in Guizhou Province, China, for physical and chemical property analysis. In total, 180 physical and 90 chemical soil samples were collected on three occasions in May, August, and December 2022. Soil fertility and quality were evaluated under various measures using membership functions and principal component analysis (PCA). This study showed that almost all measures could enhance soil water storage capacity (The average total soil porosity of 9 soil treatments was 57.56%, while that of the control group was 56.37%). With the increase in soil porosity, soil evaporation became stronger, and soil water content decreased. Nevertheless, no decrease in soil water content was observed in the presence of vegetation cover (soil water content: 16.46% of hairy vetch, 13.99% of clover, 13.77% of the control). They also proved that manure, synthetic fertilizer, and straw could promote total and available nutrients (Soil total nutrient content, or the total content of TN、TP、TK,was presented as: synthetic fertilizer (11.039g kg-2)>fowl manure (10.953g kg-2)>maize straw (10.560g kg-2)>control (9.580g kg-2);Total available nutrient content in soil, or the total content of AN,AP,A,was shown as:fowl manure (1287.670 mg kg-1)>synthetic fertilizer (925.889 mg kg-1)>sheep manure (825.979 mg kg-1)>control (445.486 mg kg-1). They could also promote soil fertility, among which the first two reached the higher comprehensive soil quality. Fertilizer was conducive to improve soil quality and fertility, yet long-term application could cause land degradation like soil non-point source pollution, compaction, and land productivity decline. Ultimately, combining fertilizer with biochar or manure is recommended to improve soil fertility. Biochar and green manure could play an apparent role in soil improvement only when there is abundant soil water. The above views provide theoretical support for curbing soil degradation, improving soil fertility and quality, enhancing land productivity, and promoting the virtuous cycle of the soil ecosystem. [ABSTRACT FROM AUTHOR]

In recent years, non-point source pollution (NPSP) has become prominent in the Yellow River Basin (YRB) of China and seriously affects human survival and sustainable development. The Henan section was selected as an example region of the YRB in China, and the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model has been used to quantitatively evaluate nitrogen (N) and phosphorus (P). The results show that (1) the cultivated land (CL), grassland (GL), and unused land (UL) decreased, while forest land (FL), water areas (WAs), and built-up areas (BAs) increased in 2000-2020, and precipitation increased from the northeast to the southwest in 2000-2020; (2) the N export was much more than P export in 2000, 2010, and 2020, and the N and P exports increased in 2000-2020; the spatial distribution of N and P export changes was different in the whole basin in 2000-2010, 2010-2020, and 2000-2020; (3) the N and P exports decreased in 2000-2010, 2010-2020, and 2000-2020 with increasing precipitation; and (4) the N and P exports on CL and BAs were more than those on the other land-use types, and the overall change trends of N and P exports on all land-use types increased from 2000 to 2020. [ABSTRACT FROM AUTHOR]

Maximizing the impact of agricultural wastewater conservation practices (CP) to achieve total maximum daily load (TMDL) scenarios in agricultural watersheds is a challenge for the practitioners. The complex modeling requirements of sophisticated hydrologic models make their use and interpretation difficult, preventing the inclusion of local watershed stakeholders' knowledge in the development of optimal TMDL scenarios. The present study develops a seamless modeling approach to transform the complex modeling outcomes of Hydrologic Simulation Program Fortran (HSPF) into a simplified participatory framework for developing optimized management scenarios. The study evaluates seven conservation practices in the Pomme de Terre watershed in Minnesota, USA, focusing on sediment and phosphorus pollutant load reductions incorporating farmers' opinions to guide practitioners toward implementing cost-effective CPs. Results show reduced tillage and filter strips are the most cost-effective practices for non-point source pollution reduction, followed by conservation cover perennials. The integration of SAM with HSPF is crucial for sustainable field-scale implementation of conservation practices through enhanced involvement of amateur-modeling stakeholders and farmers directly connected to fields. [ABSTRACT FROM AUTHOR]

The paddy field is a major source of gaseous carbon and nitrogen emissions, and reducing these emissions is of great significance for mitigating greenhouse effects and non-point source pollution in farmland. Biochar, derived from agricultural waste, possesses a stable structure, large specific surface area, abundant pore structures, and surface functional groups. These characteristics could enhance soil physicochemical properties and microbial activity, thereby facilitating the dual goals of increasing crop yield and reducing emissions. Based on numerous studies, this review summarizes the effects of biochar on the emissions of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ammonia volatilization (NH3), as well as on global warming potential (GWP) and greenhouse gas emission intensity (GHGI). It elucidates the mechanism of emission reduction by biochar amendment from the perspective of carbon and nitrogen conversion processes and soil physicochemical and biological properties. Numerous studies showed the application of 5~40 t ha−1 biochar reduced CO2, CH4, N2O, and NH3 emissions by 1.64~89.6%, 8.6~89.6%, 10~90%, and 12.27~53%, respectively. A small number of studies found that the application of 5~48 t ha−1 biochar increased CO2, CH4, N2O, and NH3 emissions by 12~37%, 19.85~176%, 13~84.23%, and 5.47~70.9%, respectively. Most scholars have found that biochar has varying degrees of emission reduction capabilities in different parts of the world. Therefore, future research directions have been suggested for utilizing biochar to reduce carbon and nitrogen emissions in paddy fields. [ABSTRACT FROM AUTHOR]

Decreased water quality in coastal environments due to land alterations by human activities has caused stressed and degraded coral reefs worldwide. The consequences of decreased water quality are not limited to coral reefs but also affect the quality of people's lives by increasing the incidence of diseases, so areas highly impacted have been prioritized for management. The Guánica Bay Watershed Management Plan was developed to reduce the non-point sources of pollution that arrive at the bay and to protect adjacent coral reefs, however, 15 years have passed since its creation and management actions have not been evaluated. The purpose of this study was to evaluate the effectiveness of the management actions implemented in the Guánica Bay watershed. Therefore, the objective of this study was to describe temporal trends (2002-2008 and 2016-2022) of remotely sensed diffuse attenuation coefficient at 490 nm (Kd490), a water quality indicator, in one managed (Guánica Bay) and three non-managed (Guayanilla Bay, Descalabrado River, and Guanajibo River) estuaries in Southwestern Puerto Rico. This was achieved by integrating ocean-color satellite imagery from MERIS-Envisat and OLCI-Sentinel-3 sensors that were sampled using a beyond-Before-After-Control-Impact (beyond-BACI) approach. An additional oceanic site was selected to evaluate continuity between sensors estimates. The imagery was processed using SNAP to extract Kd490 values in the estuaries. The analysis for the beyond-BACI found significant differences between periods (before and after) but the changes were unique to each location within estuary. The lowest Kd490 values and variability within estuary was observed in Guánica (range 0.05-0.1 m-1) and the highest Kd490 values were observed in Guayanilla (0.35 m-1). The southern estuaries showed similar temporal trends, all having a peak in 2018 and a trough in 2020. Kd490 did not decrease in Guánica after the implementation of management actions, which can be related to the passage of several hurricanes during the after period. Further analysis should be done as new data is available and after the implementation of the last management actions suggested in the plan. [ABSTRACT FROM AUTHOR]