FLT3-selective PROTAC: Enhanced safety and increased synergy with Venetoclax in FLT3-ITD mutated acute myeloid leukemia.

Acute myeloid leukemia (AML) patients carrying Fms-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) mutations often face a poor prognosis. While some FLT3 inhibitors have been used clinically, challenges such as short efficacy and poor specificity persist. Proteolytic targeting chimera (PROTAC), with its lower ligand affinity requirement for target proteins, offers higher and rapid targeting capability. Gilteritinib, used as the ligand for the target protein, was connected with different E3 ligase ligands to synthesize several series of PROTAC targeting FLT3-ITD. Through screening and structural optimization, the optimal lead compound PROTAC Z29 showed better specificity than Gilteritinib. Z29 induced FLT3 degradation through the proteasome pathway and inhibited tumor growth in subcutaneous xenograft mice. We verified Z29's minimal impact on platelets in a patient-derived xenografts (PDX) model compared to Gilteritinib. The combination of Z29 and Venetoclax showed better anti-tumor effects, lower platelet toxicity, and lower hepatic toxicity in FLT3-ITD+ models. The FLT3-selective PROTAC can mitigate the platelet toxicity of small molecule inhibitors, ensuring safety and efficacy in monotherapy and combination therapy with Venetoclax. It is a promising strategy for FLT3-ITD+ patients, especially those with platelet deficiency or liver damage.

[Coal Control and Carbon Reduction Path in Henan Province's Power Industry Under the Carbon Peak and Neutralization Target: A Medium- and Long-term Study].

Achieving peak carbon dioxide emissions and accelerating decarbonization progress in the power industry is of paramount significance to Henan Province's objective of achieving carbon peak and neutrality. In this study, the Carbon Emission-Energy Integrated Model (iCEM) was employed to conduct scenario studies on the coal reduction and carbon reduction paths under the "dual-carbon" goal of Henan's power industry. The results indicated that, by considering measures such as optimizing the power source structure and technological progress, Henan Province's power industry carbon emissions will reach their peak between 2028-2033, with coal consumption in the power industry continuing to grow during the "14th Five-Year Plan" period. With a peak range between 2027-2031, the peak value increased by 1881, 1592, and 11.48 million tce, respectively, compared with that in 2020. To control coal in Henan Province under the constraint of carbon peak goals, it is proposed to develop clean energy sources such as wind and solar power, use more low-carbon or zero-carbon heat sources, increase the proportion of external electricity supply, and enhance energy-saving transformation in coal-fired power plants. Accelerating the elimination of backward units and energy-saving transformation of existing units, accelerating non-fossil energy development, advanced planning for external electricity supply, improving market mechanisms for the exit of coal-fired power plants and peak regulation, increasing system flexibility, and accelerating external policies to ensure clean energy security are effective paths for controlling coal and reducing carbon emissions in Henan's power industry. Additionally, inland nuclear power layout is one of the crucial paths to alleviate coal control pressure in Henan Province and achieve "dual-carbon" goals during the carbon-neutral stage. Therefore, it is imperative to conduct research on demonstrations in advance. Henan Province is highly dependent on energy from other provinces, and the power supply and demand situation in Henan Province will become increasingly tense in the future. It is necessary to support Henan Province from the State Grid and coordinate the construction of inter-provincial and inter-regional power transmission channels.

Exploring the complex trade-offs and synergies of global ecosystem services.

The trade-off and synergy relationship of ecosystem services is an important topic in the current assessment. The value of each service provided by the ecosystem is substantially affected by human activities, and conversely, its changes will also affect the relevant human decisions. Due to varying trade-offs among ecosystem services and synergies between them that can either increase or decrease, it is difficult to optimize multiple ecosystem services simultaneously, making it a huge challenge for ecosystem management. This study firstly develops a global Gross Ecosystem Product (GEP) accounting framework. It uses remote sensing data with a spatial resolution of 1 km to estimate the ecosystem services of forests, wetlands, grasslands, deserts, and farmlands in 179 major countries in 2018. The results show that the range of global GEP values is USD 112-197 trillion, with an average value of USD 155 trillion (the constant price), and the ratio of GEP to gross domestic product (GDP) is 1.85. The trade-offs and the synergies among different ecosystem services in each continent and income group have been further explored. We found a correspondence between the income levels and the synergy among ecosystem services within each nation. Among specific ecosystem services, there are strong synergies between oxygen release, climate regulation, and carbon sequestration services. A trade-off relationship has been observed between flood regulation and other services, such as water conservation and soil retention services in low-income countries. The results will help clarify the roles and the feedback mechanisms between different stakeholders and provide a scientific basis for optimizing ecosystem management and implementing ecological compensation schemes to enhance human well-being.

Intramedullary Nailing Versus Open Reduction and Plate Fixation for Lateral Malleolar Fractures: A Meta-Analysis.

The fixation for lateral malleolar fracture in ankle fractures is still controversial. The purpose of this meta-analysis is to compare clinical and radiological outcomes between intramedullary nail (IMN) and plate for lateral malleolar fractures in ankle fractures. The PubMed, EMBASE, and Cochrane Library were searched for randomized controlled trials (RCTs) from databases inception to June 2023. Data on outcomes were extracted and the methodological quality of the included studies were assessed. A meta-analysis was performed using RevMan 5.3 software when the data extracted from included studies could be synthesized. Seven RCTs were included. The methodological quality of the included studies was moderate to high. The meta-analysis results showed that the infection rate of the IMN group was significantly lower than that of the plate group (RR = 0.38; 95%CI 0.18-0.82; p = .01). There were no significant differences between the 2 groups in Olerud and Molander Ankle Score (OMAS), union rate, radiological outcomes, nerve injury rate, reoperation rate, loss of reduction, and total complication rate. Our present meta-analysis demonstrated that the IMN might be a better method for the fixation of lateral malleolar fracture in ankle fracture, as the infection rate was significantly lower than a plate.

Revealing varying relationships between wastewater mercury emissions and economic growth in Chinese cities.

Mercury emission from industrial wastewater has a great impact on the aquatic environment but is not well studied. Inventory analysis, decoupling and decomposition methods have been conducted based on the China Pollution Source Census dataset, which combines industry removal efficiencies to calculate mercury emissions from industrial wastewater in 340 cities in China during 2000-2010. The results show that over these 11 years, total mercury emissions and per capita mercury emissions increased by approximately 5 times, while the emission intensity increased by only about 3%. From 2000 to 2010, only 0.59% of cities showed strong decoupling between economic growth and mercury emissions, and 37.65% of cities showed weak decoupling, whereas 38.82% of cities showed negative decoupling. We attribute the decoupling of economic development and emissions in individual cities to several socioeconomic factors and find that a decline in emission intensity is the main driver. The Gini coefficient indicates a significant imbalance between cities' emissions, but this situation improved during 2000-2010. The objective of this article is to provide a historical perspective on the situation of mercury emissions from wastewater in China, thereby contributing' to the broader understanding of industrial pollution.

The economy-employment-environmental health transfer and embedded inequities of China's capital metropolitan area: a mixed-methods study.

BACKGROUND: Metropolitan areas have complex trade linkages internally and externally. This complexity stimulates the unequal spatial transfer of environmental health consequences, economy, and employment embodied in internal trade or trade with the outside regions, resulting in unequal exchange. Existing research has rarely discussed this issue at a refined scale, hindering targeted inequity alleviation policies. METHODS: We conducted a mixed-methods study, focusing on the most polluted metropolitan area in the world, the Beijing-Tianjin-Hebei region of China, and developed an integrated modelling framework to downscale the analysis of the trade-driven unequal transfer of PM2·5- related premature deaths, value added, and job opportunities to the city scale within Beijing-Tianjin-Hebei. The study couples a nested Multi-Regional Input-Output model table containing data from 13 Beijing-Tianjin-Hebei cities and 28 outer provinces in 2017 with a bottom-up emission inventory, value added and employment statistical data, the Weather Research and Forecasting-Comprehensive Air Quality Model with Extensions, the Global Exposure Mortality Model, and human capital methods. We also constructed two indices measuring unequal exchanges between PM2·5-related deaths and economic and employment gains embodied in trades between cities in Beijing-Tianjin-Hebei and trades with outside regions. FINDINGS: The Beijing-Tianjin-Hebei region as a single entity shifted 14 985 (95% CI 12 800-16 948) net deaths to regions outside the Beijing-Tianjin-Hebei through trade, most of which occurred in the central region of China. The industrial-based peripheral Beijing-Tianjin-Hebei cities suffered the most serious inequities when trading with other Beijing-Tianjin-Hebei cities and outside regions. While gaining equivalent local jobs, these industrial-based peripheral cities had 250% higher PM2·5-related deaths (10·2 PM2·5-related deaths for obtaining 1000 local jobs) than core cities (2·9 PM2·5-related deaths for obtaining 1000 local jobs) and 57·7% higher PM2·5-related deaths than agricultural-based peripheral cities (6·5 PM2·5-related deaths for obtaining 1000 local jobs). While gaining equivalent value added, industrial-based peripheral cities had 50·6% higher PM2·5-related deaths (¥13·9 of reduced human capital due to PM2·5-related premature deaths to obtain ¥1000 local value added) than core cities (¥9·2 of reduced human capital due to PM2·5-related premature deaths to obtain ¥1000 local value added) and 67·4% higher PM2·5-related deaths than agricultural-based peripheral cities (¥8·3 of reduced human capital due to PM2·5-related premature deaths to obtain ¥1000 local value added). INTERPRETATION: Treating metropolitan areas as a single entity obscured internal heterogeneity, potentially misleading policy makers into imposing strict regulations on the whole metropolitan area to alleviate the inequities it posed on outside regions. However, several peripheral Beijing-Tianjin-Hebei cities were disadvantaged in their trade with core Beijing-Tianjin-Hebei cities and outside regions. Therefore, policies should be tailored for particular cities within metropolitan areas. Future targeted policies should include, but not be limited to, making ecological compensations and incorporating the environment and health costs into the price of pollution-intensive goods and services. FUNDING: National Key Research and Devlopment Program of China, National Natural Science Foundation of China, and Jiangsu Natural Science Foundation.

Agricultural Methane Emissions in China: Inventories, Driving Forces and Mitigation Strategies.

Identification of the spatial distribution, driving forces, and future trends of agricultural methane (AGM) emissions is necessary to develop differentiated emission control pathways and achieve carbon neutrality by 2060 in China, which is the largest emitter of AGM. However, such research is currently lacking. Here, we estimated China's AGM emissions from 2010 to 2020 and then decomposed six factors that affect AGM emissions via the LMDI model. The results indicated that the AGM emissions in China in 2020 were 23.39 Tg, with enteric fermentation being the largest source, accounting for 43.9% of the total emissions. A total of 39.3% of the AGM emissions were from western China. The main driver of AGM emission reduction was emission intensity, accounting for 59% and 33.7% of methane emission reduction in the livestock sector and rice cultivation, respectively. Additionally, higher levels of urbanization contributed to AGM emission reductions, accounting for 31.3% and 43.0% of the livestock sector and rice cultivation emission reductions, respectively. Based on the SSP-RCP scenarios, we found that China's AGM emissions in 2060 were reduced by approximately 90% through a combination of technology measures, behavioral changes, and innovation policies. Our study provides a scientific basis for optimizing existing AGM emission reduction policies not only in China but also potentially in other high AGM-emitting countries, such as India and Brazil.

Revealing Inter-regional Environmental Inequities Hidden in China's Energy Transition.

Energy transition is an important way to control air pollution, but it may conflict with the economic goal of alleviating regional inequality due to its inherently different cost burdens. As one of the effective measures of energy transition, this paper takes small coal-fired boiler (SCB) upgrading as an example to explore the regional mismatch between upgrading costs and health benefits. Here, we construct a boiler-level inventory of SCB upgrades for the North China Plain (NCP) during 2013-2017 and propose an integrated modeling framework to quantify the spatial contribution of economic costs and health benefits associated with SCB upgrading. We find that although the total health benefits could offset the total costs for the entire region, the developed municipalities (Beijing and Tianjin) are likely to gain more health benefits from less-developed neighboring provinces at lower costs. These developed municipalities contribute only 14% to the total health benefits but gain 21% of the benefits within their territories, 56% of which come from neighboring provinces. Their benefits are approximately 5.6 times their costs, which is much higher than the 1.5 benefit-cost ratio in neighboring provinces. Our findings may be useful in shaping more equitable and sound environmental policies in China or other regions of the world with serious coal-related air pollution.

Source Contributions to PM2.5-Related Mortality and Costs: Evidence for Emission Allocation and Compensation Strategies in China.

The emissions from various pollution sources were not proportional to their contributions to ambient PM2.5 concentrations and associated health burdens. That means even with the same total abatement targets, different abatement allocation strategies across emission sources can have distinct health benefits. Insufficient knowledge of various sources' contributions to health burdens in China, the country suffering substantial PM2.5-related deaths, hindered the government from seeking optimized abatement allocation strategies. In this context, we separated the contributions of 155 emission sources (31 provinces × 5 sectors) to PM2.5-related mortality across China in 2017 by coupling the Comprehensive Air Quality Model with Extensions (CAMx), Weather Research and Forecasting model (WRF), and health impact assessment model. We further identified the priority-control emission sources and quantified interprovincial ecological compensation volumes to alleviate inequality induced by emission allocation strategies. Results showed that PM2.5 pollution caused 899,443 excess deaths and around 127 billion USD costs in 2017. Approximately half of the deaths and costs were attributable to emissions from sources outside the boundary of the regions where the deaths occurred. Twenty-five out of 155 emission sources that contributed to the top 60% mortality burdens and had high marginal abatement efficiencies in China shall be the priority-control emission sources. A 1 µg/m3 decrease of PM2.5 concentration in regions where these key emission sources occur shall be compensated by 76-153 million USD in their receptor regions. Our study sheds light on the sources' contributions to mortality burdens and costs and provides scientific evidence for optimizing the emission allocation and compensation strategies in China. It also has wide implications for other countries suffering similar problems.

[Coal-carbon-pollutant Coordinated Control of Coal Chemical Industry Under Carbon Peak and Carbon Neutrality Constraints].

Under carbon peak and carbon neutrality constraints, the coal chemical industry should take stricter measures to tackle carbon reduction. Based on the intensity differences of five major coal and carbon reduction measures applied by the coal chemical industry, which include raw material structure adjustment, fuel structure adjustment, energy-saving technology transformation, terminal capture technology, and industrial structure adjustment, this study adopted the downstream sector demand method and project method, combined with the air pollution reduction model, to predict three scenarios (benchmark, policy, and enhancement) of coal chemical industry peak year and peak amount of coal consumption and carbon dioxide emission, associated with air pollutant reduction row effects. The results showed that coal consumption under the benchmark and policy scenarios of the coal chemical industry is expected to reach a peak in the late period of China's "14th Five-Year Plan", with peak values of 0.96 billion and 0.93 billion tons, respectively. By contrast, under the enhanced scenario, it is expected to peak in the early period of the "14th Five-Year Plan" with a value of 0.91 billion tons. The carbon peak will arrive in the late period of the "15th Five-Year Plan" under the benchmark scenario but in the early and late period of the "14th Five-Year Plan" under the policy and enhanced scenarios, with peak values of approximately 0.64 billion, 0.57 billion, and 0.55 billion tons, respectively. Controlling the construction scale of new coal chemical projects, tapping the space for raw material substitution, and speeding up the energy-saving technological transformation are important measures for coal and carbon control in the coal chemical industry. The implementation of coal and carbon reduction measures of the coal chemical industry will coordinately reduce air pollutant emissions, such as SO2, NOx, PM, and VOCs by 37, 43, 11, and 28 thousand tons per year after 2035.

Worsening Carbon Inequality Embodied in Trade within China.

The mismatch between trade-embodied economic benefits and CO2 emissions causes carbon inequality, which is seldom analyzed from the intracountry level, especially across a long-term period. This study applied an environmentally extended multiregional input-output model to trace this mismatch and measure the carbon inequality quantitatively within China during 2007-2017. The results show that during the past decade, China's national carbon inequality was continuously worsening with carbon Gini coefficients rising regardless of production- (0.21-0.30) or consumption-based (0.12-0.18) accounting. The regional carbon inequality was deteriorating, where less developed provinces with 20% of total value-added emitted 32.9% of total CO2 emissions in 2007, while this figure rose to 42.6% in 2017. The eastern provinces (Jiangsu and Shanghai) had entered into net economic and carbon beneficiaries keeping high trade advantages, by contrast the northwest provinces (Ningxia and Xinjiang) were trapped in a lose-lose situation with trade benefits declining by 68%. The southwest provinces (Yunnan and Guangxi) shifted from being net carbon and value-added exporters to net importers, stepping into the earlier development mode of eastern provinces. This hidden and exacerbated carbon inequality calls for regional-specific measures to avoid the dilemma of economic development and CO2 mitigation, which also gives a good reminder for the rising economies, like India.

Public Concern about Haze and Ozone in the Era of Their Coordinated Control in China.

In China, due to the implementation of the Action Plan for Prevention and Control of Air Pollution (APPCAP), the concentrations of PM2.5 (fine particulate matter) and severe haze in most cities have decreased significantly. However, at present, haze pollution in China has not been completely mitigated, and the problem of O3 (ozone) has become prominent. Therefore, the prevention and control of haze and O3 pollution have become important and noticeable issues in the field of atmospheric management. We used the Baidu search indices of "haze" and "ozone" to reflect public concerns about air quality and uncover different correlations between level of concern and level of pollution, and then we identified regions in China that require public attention. The results showed that (1) over the last decade, the search index of haze had a rapid trend of variation in line with changes in haze pollution, but that of O3 had a relatively slowly increasing trend; (2) the lag days between the peaks of public concern and the peaks of air pollution became increasingly shorter according to daily data analysis; and (3) 96 polluted cities did not receive sufficient public attention. Although periods of heavily haze-polluted weather, which affects visibility, have generated much public concern, periods of slight pollution have not received enough public attention. Public health protection and environmental participation regarding these periods of slight pollution in China deserve appropriate levels of attention.

A novel organic arsenic derivative MZ2 remodels metabolism and triggers mtROS-mediated apoptosis in acute myeloid leukemia.

PURPOSE: Acute myeloid leukemia (AML) is one of the most common neoplasms in adults, and it is difficult to achieve satisfactory results with conventional drugs. Here, we synthesized a novel organic arsenic derivative MZ2 and evaluated its ability to remodel energy metabolism to achieve anti-leukemia. METHODS: MZ2 was characterized by the average 1-min full mass spectra analysis. Biological methods such as Western blot, qPCR, flow cytometry and confocal microscopy were used to assess the mode and mechanism of MZ2-induced death. The in vivo efficacy of MZ2 was assessed by constructing a patient-derived xenograft (PDX) AML model. RESULTS: Unlike the precursor organic arsenical Z2, MZ2 can effectively reduce the level of aerobic glycolysis. Our in-depth found that MZ2 inhibited the expression of PDK2 in a dose-dependent manner and did not affect the expression of LDHA, another key enzyme of the glycolytic pathway. MZ2 reconstituted energy metabolism to induce the generation of mitochondrial ROS (mtROS) and then triggerd intrinsic apoptosis pathway. We also assessed whether MZ2 generates autophagy and results showed that MZ2 can induce autophagy of AML cells, which may be associated with the precursor organic arsenic drug. In vivo, MZ2 effectively attenuated leukemia progression in mice, and immunohistochemical results suggested its PDK2 inhibitory effect. CONCLUSION: In summary, the novel organic arsine derivative MZ2 exhibited excellent anti-tumor effects in acute myeloid leukemia, which may provide a potential strategy for the treatment of acute myeloid leukemia.

Are the Benefits of a High-Emission Vehicle Driving Area Restriction Policy Greater than the Costs?

China implemented a vehicle driving area restriction policy to control air pollution by delimiting a no-driving area for high-emission vehicles (HEVs). Current academic research does not evaluate the benefits and costs of this policy based on vehicle level and lacks evidence at the regional level. Therefore, a cost-benefit analysis method is developed to evaluate the benefits and the costs of this policy, based on 2.128 million HEVs in the Beijing-Tianjin-Hebei (BTH) region from 2008 to 2015. The benefits, the costs, and net benefits of this policy were CNY 98.49, CNY 5.80 and CNY 92.69 billion. The cost-benefit ratios of the BTH region, Beijing, Tianjin and Hebei were 1:16.98, 1:20.88, 1:14.52 and 1:16.55, respectively. Beijing's cost-benefit ratio was the maximum at the city scale. This work can provide scientific support for promoting driving area restriction policies on older gasoline vehicles and older diesel vehicles, the improvement of cost-benefit analysis and efficient decision-making for the Chinese government.

[Roadmap of Coal Control and Carbon Reduction in the Steel Industry Under the Carbon Peak and Neutralization Target].

The low-carbon green transformation and the earlier peak in coal consumption and carbon emissions of the steel industry will make important contributions to the overall carbon peaking goal and high-quality economic development in China. Based on the carbon emission-energy integration model, we conducted a scenario study on the path of coal control and carbon reduction under the "carbon peak and neutralization" target of the steel industry. The results showed that the steel industry is likely to achieve a carbon peak in the early stage of the "14th Five-Year Plan," with a peak value of 1.64-1.67 billion tons (including process and indirect emissions), and coal will also peak together as the main form of energy consumption, with a peak value of 460-470 million tons of standard coal (including coke). In the most aggressive intensification scenario, coal consumption and carbon emissions will drop to 38% and 49%, respectively, in 2035. The yield of crude steel will largely dominate the carbon peaking of the steel industry. Promoting the short process of all-scrap electric furnaces and increasing the utilization of scrap steel are the most important measures to control coal and reduce carbon in the carbon peak stage. The roadmap for coal control and carbon reduction based on the forecasted results showed that, on the demand side, the yield of crude steel will reach its peak and begin to decline, with the level of industrialization and urbanization gradually reaching the level of developed countries, even without considering the constraints of the carbon peak and neutralization target, the growth of steel demand brought about by the construction of new energy-related infrastructure during the period of achieving carbon neutrality is relatively limited. In terms of technological progress, promoting the application of long-process energy-saving and carbon-reducing technology is a cost-effective measure in the short term, and by increasing the average ratio of blast furnace pellets at the same time, the carbon capture and storage technology will have greater carbon emission reduction potential in the long term. In terms of production capacity structure, promoting the short process of all-scrap electric furnaces is the main measure of the steel industry in the carbon peak stage, and the proportion of electric furnace steel will increase to 15%-20% by the end of the "14th Five-Year Plan" period. Under the carbon neutrality target, hydrogen metallurgy is the only production process with ultra-low carbon emission potential. In the future, with the increase in the supply of green hydrogen produced by renewable energy or waste heat, hydrogen metallurgy will become a steel production process that is as important as the short process of electric furnaces based on scrap steel.

Open Search-Based Proteomics Reveals Widespread Tryptophan Modifications Associated with Hypoxia in Lung Cancer.

The tryptophan residue has a large hydrophobic surface that plays a unique role in the folded protein conformation and functions. Tryptophan modifications are presumably to be readily detected in proteins due to the vulnerability of the indole structure to electrophilic attacks. In this study, we report a systematic identification of sequence variations at tryptophan, termed tryptophan variants, from the proteome of patients with nonsmall cell lung cancer (NSCLC). Using shotgun proteomics and a modified open search algorithm, 25 tryptophan variants on 2481 sites in over 858 proteins were identified. Among these, 6 tryptophan variants are previously identified, 15 are newly annotated, and 4 are still unknown, most of which are involved in the cascade of oxidation in the blood microparticle. Remarkably, Trp313 of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was up-oxidized whereas Trp16 and Trp38 of hemoglobin (HBB) were down-oxidized in NCSLC tissues. The results were further supported by an independent cohort of 103 lung adenocarcinoma samples, reflecting a negative feedback and potential detoxification mechanism against tumor glycolysis and hypoxia. Overall, the study reports a quick approach to explore tryptophan variants at the proteomic scale. Our findings highlight the predominant role of tryptophan oxidation in regulating the redox balance of cancer cells and its potential role as prognostic biomarker for patients with NSCLC.

Synthesis of 1,3-Dioxepine-Fused (Tricyclic) Bispyrazoles Involved with Pyrazolone Derivatives and Dichloromethane.

A simple and novel method for the synthesis of novel 1,3-dioxepine-fused (tricyclic) bispyrazoles is described. It involves a Cs2CO3-mediated O-alkylation of readily available pyrazolone derivatives with dichloromethane as the methylene source followed by PhI(OAc)2-mediated intramolecular oxidative biheteroaryl coupling under mild conditions. This scalable protocol was applied for the preparation of valuable and novel 1,3-dioxepine-fused (tricyclic) bispyrazoles that could find applications in medicinal or material chemistry.

Optimal allocation and transaction of waste load permits for transboundary basin: A Bi-level programming approach based on node-arc.

Inadequate water quality exacerbates global water resources scarcity. Hence, water quality of the river basin is increasingly perceived as a global obstacle to sustainable development because of the limited water carrying capacity. Efficient waste load permits (WLPs) allocation plays a critical role in enhancing water quality by controlling the emission cap. Considering transboundary water pollution and transaction among regions, a bi-level objective model is proposed to analyze the WLPs allocation based on the node-arc method. Motivated by alleviating regional development differences, the watershed management committee concentrates on equitable distribution of WLPs to regions. Furthermore, regional authorities focus on how to guarantee the maximum economic development and balance the WLPs emissions from the municipal, industrial, and agricultural sectors. Practicality and efficiency of the constructed model is demonstrated by applying it to Tuojiang River Basin. Through the analysis of the results, three management recommendations are proposed for Tuojiang River: strengthening the prevention of agricultural non-point source pollution, sticking to the cooperation between upstream and downstream regions, and speeding up the construction of sewage environmental tax system. The results illustrate that as the proposed method can control the total amount of sewage, it could provide decision-making references for the amelioration of water environment.