Regulation Mechanism for Designing Decarbonization Pathways in the Copper Industry Toward Carbon Neutrality.

The transformation of the global power structure caused by the carbon neutrality goal will promote copper consumption. It is crucial to explore the decarbonization pathways of the copper industry to help fulfill greenhouse gas (GHG) emission reduction targets. This study utilized material flow analysis and life cycle assessment methods to investigate 12 different subscenarios based on international trade, circular economy, technology evolution, and environmental market factors. Policy combination scenario is employed to reveal the mechanism of decarbonization. The results show that refined copper consumption in China is expected to increase by 62.3% in 2060 compared to 2020. The GHG emissions of China's copper industry will reach 9.1 million tonnes (Mt) CO2e in 2060, technology evolution and environmental market are crucial for realizing carbon neutrality goal of this industry, accounting for 26.4 and 47.2% of emissions reductions, respectively, between 2020 and 2060. International trade and circular economy play important roles in the high-quality carbon peaking stage; however, imported copper and domestic secondary copper will constitute the basic supply of copper resources in China in the long run, and the comparative advantages of them will gradually weaken. Policy combination scenario can achieve the incentive synergy effect, with GHG reduced to 0.5 Mt CO2e in 2060. The enhanced application of policies such as material substitution and carbon emission trading will further promote industry to achieve net-zero GHG emission. We suggest regulating the industry's structure based on the international systemic circulation pattern and accelerating the construction of a green circular chain in the short term to achieve sustainable copper supply and high-quality carbon peaking. Promoting a high-quality technology development strategy and enhancing the environmental markets are recommended in the long term to achieve carbon neutrality.

Material Flow Analysis and Occupational Exposure Assessment in Additive Manufacturing End-of-Life Material Management.

Additive manufacturing (AM) offers a variety of material manufacturing techniques for a wide range of applications across many industries. Most efforts at process optimization and exposure assessment for AM are centered around the manufacturing process. However, identifying the material allocation and potentially harmful exposures in end-of-life (EoL) management is equally crucial to mitigating environmental releases and occupational health impacts within the AM supply chain. This research tracks the allocation and potential releases of AM EoL materials within the US through a material flow analysis. Of the generated AM EoL materials, 58% are incinerated, 33% are landfilled, and 9% are recycled by weight. The generated data set was then used to examine the theoretical occupational hazards during AM EoL material management practices through generic exposure scenario assessment, highlighting the importance of ventilation and personal protective equipment at all stages of AM material management. This research identifies pollution sources, offering policymakers and stakeholders insights to shape pollution prevention and worker safety strategies within the US AM EoL management pathways.

Increasing the Recycling of PVC Flooring Requires Phthalate Removal for Ensuring Consumers' Safety: A Cross-Checked Substance Flow Analysis of Plasticizers for Switzerland.

As our planet grapples with the severe repercussions of plastic pollution, mechanical recycling has been proposed as a potential remedy. However, increasing mechanical recycling may have unintended negative consequences. For example, recycling of PVC flooring containing hazardous plasticizers that were used in the past may lead to continued exposure. Here we propose measures to increase recycling while circumventing adverse health impacts caused by legacy additives. For this, we conduct a dynamic substance flow analysis for Switzerland and the time period from 1950 to 2100, focusing on three plasticizers: di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DiNP), and di(2-ethylhexyl) terephthalate (DEHT). We quantify the uncertainty of results, check their plausibility against measured concentrations in samples representative for the Swiss market, and compare them with modeled substance flows in Germany. Based on the cross-checked model, future average concentrations of DEHP in PVC flooring on the Swiss market are expected to be above the legal limit of 0.1 wt % for several decades if increased recycling rates are implemented without additional measures. Phasing out the potentially concerning DiNP, too, and preventing phthalates from entering recycling would lower their average market concentrations to values below 0.1 wt % and enable increasing recycling rates without compromising product safety. Analogous measures could help achieve this goal across other European countries and product groups.

Uncovering Availability of the Secondary Iron Resources in China: Integrating Material Flow Analysis and Secondary Resources Reserve Assessment.

As the largest iron and steel producer, China still cannot meet its demand of iron and steel only through domestic primary supply in the last few decades. Hence, secondary iron resources are increasingly significant in meeting China's iron supply and demand balance. However, the secondary iron resource availability in China and how it impacts the future supply demand balance were still insufficiently discussed. In this work, we developed a material flow analysis and secondary resources reserve assessment (MFA-SRRA) integrated model, assessed secondary iron resources availability, and conducted a supply demand analysis through nine scenarios for irons in China. The results showed that China's secondary iron reserves will increase from 8.9 Gt in 2021 to 14.04 to 19.01 Gt in 2050. With the increasing secondary iron supply, more than 60% of iron ore as a source of steelmaking can be replaced by 2050. Landfills, as a significant reserve of iron but always ignored, will accumulate 1.42-1.51 Gt secondary iron resources by 2050 and should be noticed to be mined and utilized in the future. Last, we suggest that promoting innovation in landfill mining technology and making sustainable material management policies are urgent to prevent these secondary iron resources from becoming real waste.

Spatiotemporal and Multilayer Trade Network Patterns of the Global Cobalt Cycle.

Recent years have witnessed increasing attempts to track trade flows of critical materials across world regions and along the life cycle for renewable energy and the low carbon transition. Previous studies often had limited spatiotemporal coverage, excluded end-use products, and modeled different life cycle stages as single-layer networks. Here, we integrated material flow analysis and complex network analysis into a multilayer framework to characterize the spatiotemporal and multilayer trade network patterns of the global cobalt cycle from 1988 to 2020. We found substantial growth and notable structural changes in global cobalt trade over the past 30 years. China, Germany, and the United States play pivotal roles in different layers and stages of the global cobalt cycle. The interlayer relationships among alloys, batteries, and materials are robust and continually strengthening, indicating a trend toward synergistic trade. However, cobalt ore-exporting countries are highly concentrated and rarely involved in later life cycle stages, resulting in the weakest relationship between the ore layer and other layers. This causes fluctuations and uncertainty in the global cobalt trade. Our model, linking industrial ecology, supply chain analysis, and network analysis, can be extended to other materials that are critical for the future green transition.

Smoothing the Phosphorus Resource Stress under the Socioeconomic Development in China.

Phosphorus (P) is the key in maintaining food security and ecosystem functions. Population growth and economic development have increased the demand for phosphate rocks. China has gradually developed from zero phosphate mining to the world's leading P miner, fertilizer, and agricultural producer since 1949. China released policies, such as designating phosphate rock as a strategic resource, promoting eco-agricultural policies, and encouraging the use of solid wastes produced in mining and the phosphorus chemical industry as construction materials. However, methodological and data gaps remain in the mapping of the long-term effects of policies on P resource efficiency. Here, P resource efficiency can be represented by the potential of the P cycle to concentrate or dilute P as assessed by substance flow analysis (SFA) complemented by statistical entropy analysis (SEA). P-flow quantification over the past 70 years in China revealed that both resource utilization and waste generation peaked around 2015, with 20 and 11 Mt of mined and wasted P, respectively. Additionally, rapidly increasing aquaculture wastewater has exacerbated pollution. The resource efficiency of the Chinese P cycle showed a U-shaped change with an overall improvement of 22.7%, except for a temporary trough in 1975. The driving force behind the efficiency decline was the roaring phosphate fertilizer industry, as confirmed by the sharp increase in P flows for both resource utilization and waste generation from the mid-1960s to 1975. The positive driving forces behind the 30.7% efficiency increase from 1975 to 2018 were the implementation of the resource conservation policy, downstream pollution control, and, especially, the circular agro-food system strategy. However, not all current management practices improve the P resource efficiency. Mixing P industry waste with construction materials and the development of aquaculture to complement offshore fisheries erode P resource efficiency by 2.12% and 9.19%, respectively. With the promotion of a zero-waste society in China, effective P-cycle management is expected.

Mapping Plastic and Plastic Additive Cycles in Coastal Countries: A Norwegian Case Study.

The growing environmental consequences caused by plastic pollution highlight the need for a better understanding of plastic polymer cycles and their associated additives. We present a novel, comprehensive top-down method using inflow-driven dynamic probabilistic material flow analysis (DPMFA) to map the plastic cycle in coastal countries. For the first time, we covered the progressive leaching of microplastics to the environment during the use phase of products and modeled the presence of 232 plastic additives. We applied this methodology to Norway and proposed initial release pathways to different environmental compartments. 758 kt of plastics distributed among 13 different polymers was introduced to the Norwegian economy in 2020, 4.4 Mt was present in in-use stocks, and 632 kt was wasted, of which 15.2 kt (2.4%) was released to the environment with a similar share of macro- and microplastics and 4.8 kt ended up in the ocean. Our study shows tire wear rubber as a highly pollutive microplastic source, while most macroplastics originated from consumer packaging with LDPE, PP, and PET as dominant polymers. Additionally, 75 kt of plastic additives was potentially released to the environment alongside these polymers. We emphasize that upstream measures, such as consumption reduction and changes in product design, would result in the most positive impact for limiting plastic pollution.

Inertia of Technology Stocks: A Technology-Explicit Model for the Transition toward a Low-Carbon Global Aluminum Cycle.

Low-carbon technologies are essential for the aluminum industry to meet its climate targets despite increasing demand. However, the penetration of these technologies is often delayed due to the long lifetimes of the industrial assets currently in use. Existing models and scenarios for the aluminum sector omit this inertia and therefore potentially overestimate the realistic mitigation potential. Here, we introduce a technology-explicit dynamic material flow model for the global primary (smelters) and secondary (melting furnaces) aluminum production capacities. In business-as-usual scenarios, we project emissions from smelters and melting furnaces to rise from 710 Mt CO2-eq./a in 2020 to 920-1400 Mt CO2-eq./a in 2050. Rapid implementation of inert anodes in smelters can reduce emissions by 14% by 2050. However, a limitation of emissions compatible with a 2 °C scenario requires combined action: (1) an improvement of collection and recycling systems to absorb all the available postconsumer scrap, (2) a fast and wide deployment of low-carbon technologies, and (3) a rapid transition to low-carbon electricity sources. These measures need to be implemented even faster in scenarios with a stronger increase in aluminum demand. Lock-in effects are likely: building new capacity using conventional technologies will compromise climate mitigation efforts and would require premature retirement of industrial assets.

Direct, Embedded, and Embodied Trade of Arsenic: 1990-2019.

International arsenic trade, physical and virtual, has resulted in considerable transfer of arsenic pollution across regions. However, no study has systematically captured, estimated, and compared physical and virtual arsenic trade and its relevant impacts. This study combines material flow analysis and embodied emission factors to estimate embedded (including direct and indirect trade) and embodied arsenic trade during 1990-2019, encompassing 18 arsenic-containing products among 244 countries. Global embedded arsenic trade increased considerably from 47 ± 7.3 to 450 ± 68 kilotonnes (kt) during this time and was dominated by indirect arsenic trade, contributing 94 and 90% to global arsenic trade in 1990 and 2019, respectively. Since the 1990s, global arsenic trade centers and the main flows have shifted from European and American markets to developing countries. The mass of arsenic involved in embodied trade increased from 87.5 ± 26 kt in 1990 to 800 ± 236 kt in 2019. Direct trade and indirect trade aggravate arsenic environmental emissions in major importing countries, like China, while embodied trade aggravates arsenic environmental emissions in major exporting countries, like Peru and Chile. The trade-related arsenic pollution transfer calls for a rational arsenic emission responsibility-sharing mechanism and corresponding policy recommendations for different trading countries.

Brominated Flame Retardants (BFRs) in China Over the Past Half-Century: Stocks, Flows, Fates, and Ecological Risks.

China is a significant producer and consumer of various brominated flame retardants (BFRs), raising environmental concerns due to their widespread presence and potential threats to ecosystems and organisms. This study adopts a life cycle perspective, combining material flow analysis, multimedia environmental modeling, and ecological risk assessment to systematically analyze the substance metabolism and ecological risks of six BFR types in China from 1970 to 2021. The findings reveal that China's cumulative BFR consumption reached 3.3 Mt, with the electronics sector being the predominant contributor at 52.1%. Consequently, 1.5 kt of BFRs were released into the environment, with 24.9%, 31.5%, and 43.6% being discharged into the air, water, and soil, respectively. Notably, the proportion of novel BFRs in emissions has steadily increased over the years, exemplified by the increase in decabromodiphenyl ethane (DBDPE) from 21.3% in 2010 to 30.1% in 2021. Geographically, BFR concentrations are higher in the eastern and southwestern regions compared to those in the northwest. Presently, certain BFRs like tetrabromobisphenol A (TBBPA) and DBDPE exhibit moderate to high ecological risks, primarily concentrated in the Shandong and Sichuan provinces. A combination of efficient recycling, emission control, and substitution with novel flame-retardant can minimize the exposure of BFRs to the environment and organisms.

Life-Cycle Environmental Impacts of Additive-Related Chemicals in Polyvinyl Chloride Plastics and the Mitigation Potential.

Plastic additive-related chemicals, particularly in polyvinyl chloride (PVC) plastics, have become a key issue in plastic pollution. Although addressing plastic pollution through the life-cycle approach is crucial, the environmental impacts of typical plastic additive-related chemicals in PVC plastics during the cradle-to-gate stage remain unexplored. Consequently, managing the life-cycle environmental impacts of these additives remains challenging. Herein, the environmental impacts of 23 typical plastic additive-related chemicals and six PVC plastic products were evaluated throughout the cradle-to-gate life-cycle stage using a life cycle assessment-material flow analysis (LCA-MFA) coupled model. The results indicate that plastic additives significantly contribute to the environmental impacts of PVC plastic products across various end point indicators, ranging from 8.7 to 40.6%. Additionally, scenario analysis (SA) reveals that conventional strategies for addressing plastic pollution may not be highly effective in mitigating the environmental impacts associated with plastic additives. Specifically, compared to primary polymers, these additives exhibit 4 to 13% lower mitigation potential under the same policy scenarios. However, technical adjustment strategies targeting additives show a mitigation potential of 12 to 39%, suggesting that guiding the plastic additive industry toward green transformation is a key strategy for reducing environmental impacts.

Mass-Balance-Consistent Geological Stock Accounting: A New Approach toward Sustainable Management of Mineral Resources.

Global resource extraction raises concerns about environmental pressures and the security of mineral supply. Strategies to address these concerns depend on robust information on natural resource endowments, and on suitable methods to monitor and model their changes over time. However, current mineral resources and reserves reporting and accounting workflows are poorly suited for addressing mineral depletion or answering questions about the long-term sustainable supply. Our integrative review finds that the lack of a robust theoretical concept and framework for mass-balance (MB)-consistent geological stock accounting hinders systematic industry-government data integration, resource governance, and strategy development. We evaluate the existing literature on geological stock accounting, identify shortcomings of current monitoring of mine production, and outline a conceptual framework for MB-consistent system integration based on material flow analysis (MFA). Our synthesis shows that recent developments in Earth observation, geoinformation management, and sustainability reporting act as catalysts that make MB-consistent geological stock accounting increasingly feasible. We propose first steps for its implementation and anticipate that our perspective as "resource realists" will facilitate the integration of geological and anthropogenic material systems, help secure future mineral supply, and support the global sustainability transition.

Carbon reduction trade-off between pretreatment and anaerobic digestion: A field study of an industrial-scale biogas plant.

With the implementation of municipal solid waste source segregation, the enormous sorted biogenic waste has become an issue that needs to be seriously considered. Anaerobic digestion, which can produce biogas and extract floating oil for biodiesel production, is the most prevalent treatment in China for waste management and greenhouse gas (GHG) emissions reduction, in accordance with Sustainable Development Goal 13 of the United Nations. Herein, a large-scale biogas plant with a capacity of 1000 tonnes of biogenic waste (400 tonnes of restaurant biogenic waste and 600 tonnes of kitchen biogenic waste) per day was investigated onsite using material flow analysis, and the parts of the biogas plant were thoroughly analyzed, especially the pretreatment system for biogenic waste impurity removal and homogenization. The results indicated that the loss of the total biodegradable organic matter was 41.8% (w/w) of daily feedstock and the loss of biogas potential was 18.8% (v/v) of daily feedstock. Life cycle assessment revealed that the 100-year GHG emissions were -61.2 kgCO2-eq per tonne biogenic waste. According to the sensitivity analysis, pretreatment efficiency, including biodegradable organic matter recovery and floating oil extraction, considerably affected carbon reduction potential. However, when the pretreatment efficiency deteriorated, GHG benefits of waste source segregation and the subsequent biogenic waste anaerobic digestion would be reduced.

Investigating the characteristics of combustible fraction of legacy waste: A study on energy recovery potential and GHG emission quantification.

In India, majority of the generated municipal solid waste (MSW) was dumped in poorly managed landfills and dumpsites over the past decades and is an environmental and health hazard. Landfill mining is a promising solution to reclaim these sites along with the recovery of resources (materials and energy). During landfill mining operations, the combustible fraction is one of the major components recovered and needs proper management for maximizing resource recovery. For the identification of appropriate resource recovery options, knowledge of the physicochemical characteristics is required. The present study aims to assess the depth-wise change in the composition of legacy waste and the physicochemical characteristics of the combustible fraction. Furthermore, a material flow analysis considering the incineration of combustible fraction was performed to estimate the energy generation potential and the associated greenhouse gas (GHG) emissions. The results of the compositional analysis of dry legacy waste revealed that the fine fraction (<4 mm soil-like material) was dominating with a share of 36%. The depth-wise analysis showed a decrease in the calorific value with increasing landfill depth, while no specific trend was observed for the other parameters analyzed, including proximate and ultimate analysis, and chlorine content. The material flow analysis performed for 100 tonnes of wet legacy waste indicated that 52 tonnes of waste is combustible fraction. The GHG emissions through incineration of one tonne of dry combustible fraction would be 1389 kg CO2-eq, with 1125 kWh of electrical energy generation potential.

Computational investigation of outflow graft variation impact on hemocompatibility profile in LVADs.

BACKGROUND: Hemocompatibility-related adverse events (HRAE) occur commonly in patients with left ventricular assist devices (LVADs) and add to morbidity and mortality. It is unclear whether the outflow graft orientation can impact flow conditions leading to HRAE. This study presents a simulation-based approach using exact patient anatomy from medical images to investigate the influence of outflow cannula orientation in modulating flow conditions leading to HRAEs. METHODS: A 3D model of a proximal aorta and outflow graft was reconstructed from a computed tomography (CT) scan of an LVAD patient and virtually modified to model multiple cannula orientations (n = 10) by varying polar (cranio-caudal) (n = 5) and off-set (anterior-posterior) (n = 2) angles. Time-dependent computational flow simulations were then performed for each anatomical orientation. Qualitative and quantitative hemodynamics metrics of thrombogenicity including time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), endothelial cell platelet activation potential (ECAP), particle residence time (PRT), and platelet activation potential (PLAP) were analyzed. RESULTS: Within the simulations performed, endothelial cell activation potential (ECAP) and particle residence time (PRT) were found to be lowest with a polar angle of 85°, regardless of offset angle. However, polar angles that produced parameters at levels least associated with thrombosis varied when the offset angle was changed from 0° to 12°. For offset angles of 0° and 12° respectively, flow shear was lowest at 65° and 75°, time averaged wall shear stress (TAWSS) was highest at 85° and 35°, and platelet activation potential (PLAP) was lowest at 65° and 45°. CONCLUSION: This study suggests that computational fluid dynamic modeling based on patient-specific anatomy can be a powerful analytical tool when identifying optimal positioning of an LVAD. Contrary to previous work, our findings suggest that there may be an "ideal" outflow cannula for each individual patient based on a CFD-based hemocompatibility profile.

Viral AMGs-driven pentose phosphate pathway in natural wetland.

Viruses exist anywhere on earth where there is life, and among them, virus-encoded auxiliary metabolic genes (AMGs) can maintain ecosystem balance and play a major role in the global ecosystem. Although the function of AMGs has been widely reported, the genetic diversity of AMGs in natural ecosystems is still poorly understood. Exploring the genetic diversity of viral community-wide AMGs is essential to gain insight into the complex interactions between viruses and hosts. In this article, we studied the phylogenetic tree, principal co-ordinates analysis (PCoA), α diversity, and metabolic pathways of viral auxiliary metabolism genes involved in the pentose phosphate pathway (PPP) through metagenomics, and the changes of metabolites and genes of host bacteria were further studied by using Pseudomonas mandelii SW-3 and its lytic phage based on metabolic flow and AMGs expression. We found that the viral AMGs in the Napahai plateau wetland were created by a combination of various external forces, which contributed to the rich genetic diversity, uniqueness, and differences of the virus, which promoted the reproduction of offspring and better adaptation to the environment. Overall, this study systematically describes the genetic diversity of AMGs associated with the PPP in plateau wetland ecosystems and further expands the understanding of phage-host unique interactions.

A Synergistic Overview between Microfluidics and Numerical Research for Vascular Flow and Pathological Investigations.

Vascular diseases are widespread, and sometimes such life-threatening medical disorders cause abnormal blood flow, blood particle damage, changes to flow dynamics, restricted blood flow, and other adverse effects. The study of vascular flow is crucial in clinical practice because it can shed light on the causes of stenosis, aneurysm, blood cancer, and many other such diseases, and guide the development of novel treatments and interventions. Microfluidics and computational fluid dynamics (CFDs) are two of the most promising new tools for investigating these phenomena. When compared to conventional experimental methods, microfluidics offers many benefits, including lower costs, smaller sample quantities, and increased control over fluid flow and parameters. In this paper, we address the strengths and weaknesses of computational and experimental approaches utilizing microfluidic devices to investigate the rheological properties of blood, the forces of action causing diseases related to cardiology, provide an overview of the models and methodologies of experiments, and the fabrication of devices utilized in these types of research, and portray the results achieved and their applications. We also discuss how these results can inform clinical practice and where future research should go. Overall, it provides insights into why a combination of both CFDs, and experimental methods can give even more detailed information on disease mechanisms recreated on a microfluidic platform, replicating the original biological system and aiding in developing the device or chip itself.

Assessment of Red Blood Cell Aggregation in Preeclampsia by Microfluidic Image Flow Analysis-Impact of Oxidative Stress on Disease Severity.

Preeclampsia (PE) is a hypertensive disease characterized by proteinuria, endothelial dysfunction, and placental hypoxia. Reduced placental blood flow causes changes in red blood cell (RBC) rheological characteristics. Herein, we used microfluidics techniques and new image flow analysis to evaluate RBC aggregation in preeclamptic and normotensive pregnant women. The results demonstrate that RBC aggregation depends on the disease severity and was higher in patients with preterm birth and low birth weight. The RBC aggregation indices (EAI) at low shear rates were higher for non-severe (0.107 ± 0.01) and severe PE (0.149 ± 0.05) versus controls (0.085 ± 0.01; p < 0.05). The significantly more undispersed RBC aggregates were found at high shear rates for non-severe (18.1 ± 5.5) and severe PE (25.7 ± 5.8) versus controls (14.4 ± 4.1; p < 0.05). The model experiment with in-vitro-induced oxidative stress in RBCs demonstrated that the elevated aggregation in PE RBCs can be partially due to the effect of oxidation. The results revealed that RBCs from PE patients become significantly more adhesive, forming large, branched aggregates at a low shear rate. Significantly more undispersed RBC aggregates at high shear rates indicate the formation of stable RBC clusters, drastically more pronounced in patients with severe PE. Our findings demonstrate that altered RBC aggregation contributes to preeclampsia severity.

Identifying leverage points using material flow analysis to circularise resources from urban wastewater and organic waste.

Anthropogenic systems are synonymous with linear economies that cause widespread resource waste and environmental degradation. Urban areas are hotspots for this behaviour due to their high population density and resource consumption. Changing this situation is limited by the lack of a holistic but sufficiently detailed understanding of system units where resource waste occurs. The objectives of this study were: (1) to develop and apply a model of the material and substance (nitrogen, phosphorus, and carbon) flows of organic waste and wastewater systems at a local scale, taking Christchurch, New Zealand, as a study case, and (2) to identify leverage points within the system to achieve resource circularisation. Results show that groundwater, infiltrated water, and industrial wastewater are the predominant material flows into the system. Nitrogen and phosphorus inputs predominantly come from food products, detergents, green waste, and industrial wastewater. The Christchurch wastewater system is a prime example of a linear economy, where ∼66 % of the nitrogen and ∼63 % of the phosphorus entering the wastewater system is discharged to the ocean. Leakage from the water supply system reduces water resource efficiency, while water infiltration into the wastewater network inflates the quantity of wastewater treated at the centralised treatment plant, limiting nutrient recovery. In the compost facility, 86 % of the waste is composted, with 33% of the nitrogen and all the phosphorus exiting as compost, while ∼66 % of the nitrogen treated exits through volatilisation. The remaining 14 % of the organic waste entering the treatment plant is deemed unsuitable for composting and is landfilled. The material and substance flow analysis allowed the identification of flows with leverage points in the system where there are opportunities to reduce, reuse, or recover materials and substances to encourage circularisation. These flows include food products, detergents, unsuitable materials for composting, domestic water supply leakages, wastewater network infiltration, and wastewater treatment plant's nutrient recovery.

Spatial-temporal differentiation and control strategies of nitrogen environmental loss in China's coastal regions based on flow analysis.

Nitrogen pollution emissions from human production and living activities in coastal regions are important topics in the management of environmental pollution in coastal waters. However, to date, there has been relatively little research systematically assessing the environmental loss of nitrogen (NEL) from human activities that negatively affect marine ecosystems. This study categorised emission sources into five subsystems, namely livestock, farming, aquatic, industrial, and residential. Through flow analysis, the anthropogenic emissions of nitrogen in the gas, liquid, and solid phases from 11 coastal provinces in China in 2011, 2015, and 2020 were determined. A nitrogen cost index was constructed by combining the social indicators of each province. The effectiveness of nitrogen emission control since the land-sea coordination and the future challenges for the coastal region were discussed from various perspectives. The results of the study showed that the total NEL that poses a potential threat to marine ecosystems in coastal areas of China has decreased from 18.93 TgN to 14.66 TgN since the proposal of land-sea coordination, with livestock systems and aquatic systems emitting the most. The Bohai and Yellow Seas area were most threatened by nitrogen pollution. Among the three oceanic pathways, liquid-phase nitrogen discharge from each subsystem was effectively controlled, and the control of gas-phase nitrogen emissions is still the most numerous NEL state, although it has had a significant effect. The results of the correlation analysis suggest that NEL flow can characterize the regional management of nutrient-based organic pollutants. Past management tools and environmental investments in China have been more effective in controlling emissions from point and line sources involving artificial facilities, but less direct effect on mariculture. How to control surface source pollution from livestock and aquaculture will be an important challenge to reduce reactive nitrogen emissions in the future.