Ecological Environment Problems Research Articles

Multi-Scenario Simulation and Eco-Environmental Effects Analysis of Land Use/Cover Change in China by an Integrated Cellular Automata and Markov Model

Land use transitions play a critical role in ecological environmental restoration, but they are also plagued by ecological environmental problems caused by excessive land resource development. In this study, we propose a methodological framework for unveiling the nexus profile of land use/cover change (LUCC) and eco-environmental effects. This study explored the spatiotemporal evolution patterns of LUCC over a long time series based on high-precision land use data from 1990 to 2020. Then, the ecological values (EVs) of various cities were calculated to obtain the ecological contribution rate of different land use types in the process of change. Finally, the future development trends of land use and ecological environmental quality were predicted under multiple scenarios using the cellular automata–Markov model, and scientific policy recommendations were proposed. The results showed that the expansion trajectory of the construction land in the urban agglomeration mainly expanded inwards along the mouth of the Pearl River, and the conversion of cultivated land to construction land was the most significant type of land use change. The overall ecological environmental quality of the study area showed a downwards trend, with Shenzhen exhibiting the largest decrease in EVs. Cultivated land contributed significantly to improving regional ecological environmental quality, while the land use transition types with relatively large contributions to environmental quality deterioration were conversions to construction land. Under the scenario of coordinated protection, the degree of cultivated land area reduction was significantly reduced, and the area of forestland showed a positive growth trend, with the expansion trend of construction land being reversed. These research findings can enrich the theoretical research on the sustainable development of urban agglomerations and provide reliable data support for policy-making.

Spatial–temporal evolution and peer effects of urban green development efficiency in China

In the process of global urban development, there are urgent ecological security and environmental pollution problems, green development is the fundamental way for urban sustainable development, economic transformation and mitigation of ecological and environmental problems. Based on the panel data of 283 cities at prefecture level and above in China from 2003 to 2017, this paper analyzes spatial–temporal evolution characteristics of urban green development efficiency (UGDE) and the peer effects of UGDE between cities of different grades. It is found that during the study period, in terms of temporal evolution, the average UGDE in China increased from 0.47 in 2003 to 0.61 in 2017, with a cumulative growth rate of 29.79%, showing a rising trend in general. In terms of spatial evolution, the number of low-efficiency cities and medium-efficiency cities continued to decrease. The eastern region has always been the main distribution area of higher-efficiency cities and high-efficiency cities; in the central region, UGDE in most cities improved significantly; in the western region, UGDE has always lagged behind that in the eastern and central regions. In addition, the center of gravity of UGDE presented a trend of northwest migration in general, with a total displacement of 100.07 km, and UGDE showed a spatial dispersion trend. The empirical results indicate that the improvement of UGDE in large cities has a driving effect on that in neighboring medium cities and small cities through the positive peer effect, and the growth of UGDE in medium cities has a promoting effect on that in neighboring small cities through the positive peer effect; the increase of UGDE in medium cities has a positive peer effect on that in neighboring large cities, and the growth of UGDE in small cities has a positive peer effect on that in neighboring medium cities; UGDE promotes each other between large cities through the positive peer effect.

Urban ecological human settlements design based on green and low-carbon concept

In recent years, the continuous growth of global carbon emissions has brought about climate change and global ecological environment problems, as well as severe challenges to the development of human settlements. Based on the concept of low carbon, this paper analyzes and summarizes the current situation of green space in typical residential areas, and quantifies its annual carbon sequestration. Then this paper discusses the design optimization strategy to improve its carbon sink efficiency based on the current situation. Finally, the effectiveness and enforce ability of the optimization strategy are verified by estimating the annual carbon sequestration increase value of the green space after the optimization strategy is applied to an example. The method has a certain reference value for the design and research of urban ecological human settlements with the concept of green and low carbon.

Analysis of Paudyal’s “The Parrot in the Cage” and Sama’s “Don’t Cut down the Trees, Brother Woodcutter” from Ecological Perspectives

This paper analyzes the ecological reading of Paudyal’s “The Parrot in the Cage” and Sama’s “Don’t Cut down the Trees, Brother Woodcutter.” There are several factors of modernization responsible for the destruction of natural phenomena. The deterioration of flora and fauna has not been controlled though several government monitoring agencies have been actively working. There are limited research works on Nepali writers’ works regarding environmental issues. This study explores these two authors’ works to show how the deforestation and destruction of the wild lives take place. The findings of the study show that people are cutting down trees; hunters are hunting birds and animals; and the government is cutting down trees for constructing roads, airports, and city planning. Because of these causes, the ozone layer has been depleted; global warming has increased and people are suffering from skin cataracts; eye cataracts, and respiratory problems. The over-superiority complex of man has helped destroy the flora and fauna. Whatever change takes place in nature is irreversible. The study adopts the deep ecology theory that was propounded by Norwegian philosopher Arne Naess. This essay explains the causes and effects of deforestation. The study also analyses the related consequences of deforestation. This is explanatory research rather than exploratory. The main purpose of this paper is to minimize ecological degradation and environmental problems. The study also attempts to find necessary solutions like afforestation, reforestation, and alternative energy.

Rapid discrimination and ratio quantification of mixed antibiotics in aqueous solution through integrative analysis of SERS spectra via CNN combined with NN-EN model

IntroductionAbusing antibiotic residues in the natural environment has become a severe public health and ecological environmental problem. The side effects of its biochemical and physiological consequences are severe. To avoid antibiotic contamination in water, implementing universal and rapid antibiotic residue detection technology is critical to maintaining antibiotic safety in aquatic environments. Surface-enhanced Raman spectroscopy (SERS) provides a powerful tool for identifying small molecular components with high sensitivity and selectivity. However, it remains a challenge to identify pure antibiotics from SERS spectra due to coexisting components in the mixture. ObjectivesIn this study, an intelligent analysis model for the SERS spectrum based on a deep learning algorithm was proposed for rapid identification of the antibiotic components in the mixture and quantitative determination of the ratios of these components. MethodsWe established a water environment system containing three antibiotic residues of ciprofloxacin, doxycycline, and levofloxacin. To facilitate qualitative and quantitative analysis of the SERS spectra antibiotic mixture datasets, we developed a computational framework integrating a convolutional neural network (CNN) and a non-negative elastic network (NN-EN) method. ResultsThe experimental results demonstrate that the CNN model has a recognition accuracy of 98.68%, and the interpretation analysis of Shapley Additive exPlanations (SHAP) shows that our model can specifically focus on the characteristic peak distribution. In contrast, the NN-EN model can accurately quantify each component's ratio in the mixture. ConclusionIntegrating the SERS technique assisted by the CNN combined with the NN-EN model exhibits great potential for rapid identification and high-precision quantification of antibiotic residues in aquatic environments.

Quantitative Characterization and Disturbance Law of Key Parameters Influencing Deformation of Overlying Strata during Strip Filling in a Goaf

Strip filling mining in a goaf is of great significance for solving the ‘three under’ coal-pressure and mining-area ecological environment problems in Central and Eastern China, but the disturbance characteristics of filling parameters on overlying rock are not clear at present. Taking the geological conditions of the CT30101 working face in Mahuangliang coal mine and the short-wall interval strip filling as a background, the strength parameters (cohesion and friction angle), deformation parameters (elastic modulus and Poisson’s ratio), and structural parameters (strip width and spacing) of the filling body were selected as experimental factors, and the maximum settlement of the direct roof and the ground surface was taken as the evaluation index. The influence degree of each factor was quantitatively characterized via a variance analysis and an F test, and the main control factors of the strip filling overburden settlement were proposed. The roof and surface displacement, the stress evolution law of the filling body, and the shape change of the surrounding rock plastic zone under different levels of main control factors in the entire process of mining filling coupling were analyzed in detail. The results showed that the cohesion of the backfill had a highly significant impact on the direct roof settlement, the strip spacing and the friction angle of backfill had a significant impact on it, the cohesion of the backfill and the strip spacing had a certain impact on the surface settlement, and the two had a cross-coupling effect. In the process of mining and filling, the stress evolution of the filling body was extremely complex, and it finally presented a saddle shape that was high on both sides and low in the middle; the majority of the strata and the filling body primarily exhibited shear damage, with a small amount of tensile failure zones appearing only in the direct roof and mid-section of the filling body. The above conclusions have a certain guiding significance for the optimal design of strip filling in a goaf.

Driving factors analysis of spatial-temporal evolution of vegetation ecosystem in rocky desertification restoration area of Guizhou Province, China.

The investigation of the temporal-spatial characteristics and driving factors of vegetation ecosystem (VE) alterations held significant practical implications for the evaluation of the efficacy of rocky desertification management initiatives and safeguarding the ecological environment in the rocky desertification restoration region of Guizhou. We computed the comprehensive ecological quality index (Q) of vegetation based on the normalized difference vegetation index (NDVI) and net primary productivity (NPP). Combined with temperature, precipitation, sunshine duration, rocky desertification grade, land use, and the time series of various regions being included in national ecological functional zones, we analyzed the spatial-temporal distribution characteristics of VE changes and their response to climate change (CC) and ecological engineering (EE) by using partial derivative analysis method and scenario setting method in rocky desertification restoration areas in Guizhou. Results demonstrated that (1) the average values of NDVI, NPP, and Q all showed a fluctuating upward trend since 2000. Although the VE status of rocky desertification area was obviously worse than that of no rocky desertification area, it has a higher growth rate, especially the growth rates of NDVI, NPP, and Q in severe rocky desertification area were as high as 0.0050 year-1, 9.0733 g C m-2 year-1, and 0.7829 year-1, and the area with high recovery degree accounted for 93.19%, followed by the middle rocky desertification area. (2) CC was the main driving factor for NDVI and Q recovery, and EE was the main driving factor for NPP recovery. The contribution of EE to NPP and Q recovery increased with the increase of rocky desertification, as high as 82.13% and 30.31% in severe rocky desertification area. (3) The more serious the rocky desertification was, the more dependent the vegetation restoration was on ecological engineering, and the more difficult the restoration was. It was urgent to solve the ecological environmental problems. (4) EE played a greater role in the restoration of VE in the early stage of implementation. Its role gradually decreased in the later stages of implementation, while the role of CC increased. We provide a scientific basis for the follow-up treatment of rocky desertification, ecological environment restoration, and ecological protection effectiveness evaluation in Guizhou.

Mechanism of transport and toxicity response of Chlorella sorokiniana to polystyrene nanoplastics

The toxicity of nanoparticles to freshwater microalgae is of significant importance in maintaining the overall stability of aquatic ecosystems. However, the transport mechanism and toxicity response of microalgae towards nanoplastics (NPs) remain to be further investigated. In this study, we examined the toxicity and internalization mechanisms of polystyrene nanoplastics (PS-NPs) in the microalga Chlorella sorokiniana. The results revealed that the PS-NPs inhibited algal cells’ growth and disrupted cell integrity upon contact, leading to cell shrinkage or rupture. Moreover, amino-modified PS-NPs (Nano-PS-NH2) exhibited greater toxicity to C. sorokiniana than carboxyl-modified PS-NPs (Nano-PS-COOH). Furthermore, significant inhibition of PS-NPs internalization was observed when four different endocytosis-related inhibitors were used, indicating that internalized PS-NPs can enter algal cells through endocytic pathways. More importantly, C. sorokiniana exposed to Nano-PS-NH2 responded to the reduction in carbon sources and energy resulting from the suppression of photosynthesis by regulating the metabolism of carbohydrates. These findings elucidate the effects of PS-NPs on C. sorokiniana, including their impact on cell morphology and metabolism, while shedding light on the internalization mechanisms of NPs by C. sorokiniana which deepen our understanding of the toxicity of nanoplastics on algae and provide important theoretical support for solving such aquatic ecological environment problems.

Coupling coordination degree analysis and spatiotemporal heterogeneity between water ecosystem service value and water system in Yellow River Basin cities

Accelerated urbanization has caused encroachment on urban water ecological land in China's Yellow River basin, resulting in a strong disturbance of water ecosystem service functions and increasingly serious water ecological environmental problems. In this study, two entities—water ecosystem service value (WESV) and the urban water system—are identified, to investigate the interactions between WESV and the urban water systems and their subsystems in six Yellow River basin cities (Lanzhou, Yinchuan, Hohhot, Xi'an, Zhengzhou, and Jinan) from 2005 to 2020. First, the integrated level of the WESV and the water system in each city is calculated using the modified and developed method of equivalence factor per unit area and the entropy method, respectively. Then, the coupling coordination relationship and interactions between WESV and the water system in each city are revealed by using the coupling coordination degree model (CCDM) and the Geographically and Temporally Weighted Regression (GTWR). The results show that: 1) The level of both WESV and the water system in each city basically shows an increasing trend, the hydrological regulation function dominates the water ecosystem service functions, and the comprehensive evaluation level of the water environment is generally higher than that of the other urban water system's subsystems. 2) The degree of coupling coordination between WESV and the water system in each city gradually rose from extreme incoordination to basically coordination, and the coupling coordination degree (CCD) between WESV and the water environment and the water resources also shows an obvious upward trend, but the CCD between WESV and water safety is developing more slowly. 3) The area where the WESV and the water system have greater positive impacts are primarily focused in Lanzhou and Xi'an, while the negative impacts are mainly located in Yinchuan and Zhengzhou. In summary, in the planning and decision-making of cities in the Yellow River basin or other basin cities, it is critical to promote the protection of water ecology and high-quality development in cities by clearly understanding the interaction between water ecosystem services and the water system, and coordinating and balancing development between the two systems.

Effective Solutions to Ecological and Water Environment Problems in the Sanjiang Plain: Utilization of Farmland Drainage Resources

The Sanjiang Plain stands as a pivotal grain-producing region in China. Faced with population growth and the imperative of ensuring food security, the rapid expansion of agricultural land in the Sanjiang Plain has led to escalating ecological and water-environmental challenges, hindering the sustainable development of regional agriculture. This research aims to explore and propose practical measures for utilizing agricultural drainage resources to address the ecological and water-environmental issues resulting from agricultural expansion in the Sanjiang Plain, striving to achieve harmonious and sustainable economic and environmental growth. The discussion revolves around the potential alleviation of water quality, water quantity, and ecological health issues in the Sanjiang Plain through the proposed approach. Considering regional characteristics, the focus is on potential environmental drawbacks resulting from the improper application of the method. Building on these findings, effective strategies are presented to enhance the systematic operation of agricultural drainage resource utilization in the region. In conclusion, addressing ecological and water-environmental challenges stemming from local agricultural development is imperative for the Sanjiang Plain to realize sustainable development for the economy and the environment.

The Ginkgo biloba L. in China: Current Distribution and Possible Future Habitat

With the increase in global temperature, the global change situation dominated by climate warming is becoming more and more serious. Climate change will cause differences in the suitable areas of species in different periods. Ginkgo biloba L., a rare and endangered wild plant protected at the national level in China, is the oldest relict plant in the world. Because of severe climate change, only China’s wild Ginkgo biloba has been preserved, yet China’s wild Ginkgo biloba population is facing extinction risk. Ginkgo biloba has rich ornamental value, application value, economic value, medicinal value and ecological value. Not only can it produce economic and ecological benefits, but it can also produce huge social benefits. Based on the data of Ginkgo biloba sample distribution, bioclimatic variables and soil variables, this paper uses the MaxEnt model to simulate Ginkgo biloba suitable area under current and future different climate scenarios, and analyzes the changes in the potential suitable area of Ginkgo biloba in the future through ArcGIS 10.6. The results are as follows: (1) the results simulated by the MaxEnt model are AUC > 0.9, showing that the simulation results have a high accuracy; (2) the min temperature of the coldest month, precipitation of the wettest month, elevation, and temperature seasonality are the main environmental variables affecting the change in the Ginkgo biloba suitable area; (3) under future climate scenarios, the suitable area of Ginkgo biloba is predicted to expand in the future, covering most of the south and some northeast regions, and moderate temperature and precipitation changes under climate change are conducive for the growth of Ginkgo biloba; and (4) in the future, the distribution center of the suitable area will move to the northeast. According to the conclusions in this paper, it is expected to provide theoretical reference for cultivation and management, sustainable utilization and solution of ecological environment problems of Ginkgo biloba.

Discussion on Comprehensive Utilization and Ecological Management of Coal Gangue

Coal production will continue to increase year by year, and the amount of waste discharged will also increase year by year. In addition, the amount of coal waste accumulated in the past is quite huge. In order to implement the concept of ecological civilization in the new era, reduce the atmospheric, water, and ecological environmental problems caused by the accumulation of coal gangue in the region, solve the safety and environmental risks of existing waste disposal sites, restore the ecological and environmental functions of waste disposal sites and surrounding areas, and improve the comprehensive utilization rate of coal gangue, in accordance with relevant policies such as environmental protection and resource comprehensive utilization, and the requirements for the construction of a "waste free city" in Shenmu City, Combining the actual needs of creating a "waste free enterprise". Therefore, the comprehensive utilization and ecological management of coal gangue has become an urgent and urgent social issue that needs to be studied and solved.

Spatio-temporal evolution of land use and its eco-environmental effects in the Caohai National Nature Reserve of China

With the rapid development of social economy, the ecological environment problems caused by the change of wetland land use have been widely concerned. This paper takes the Caohai National Nature Reserve (CNNR) of China as the research object on the basis of referring to previous research results. Firstly, the remote sensing data was employed to examine the spatio-temporal evolution process of the CNNR from three aspects: land use structure change, land use dynamic degree and land use space change. Then the change of ecological environment quality was studied from the greenness, the wetness, the dryness and the heat. Based on the spatiotemporal changes of land use types and ecological environment quality in the CNNR from 2000 to 2020, a comprehensive index, the remote sensing ecological index (RSEI), was constructed to analyze the ecological environmental effects of land use changes. The results indicate that the land use changes in the CNNR went through two major periods: first, a period of rapid decline in cultivated land, and second, a period of sharp increase in constructed land. During the period of rapid decline in cultivated land, the ecological environment quality in the study area showed an upward trend. However, during the period of increased constructed land, the ecological environment quality gradually stabilized. This study provides a basis for the coordinated development of the ecological environment and social economy in the CNNR area.

Environment, Ethics, and Entity Economics, Economia Aziendale. Historical and Ontological Aspects

The paper stresses the failure of ‘economics’ to predict and prevent repeated economic crises and the most critical topic of the environmental failure and ecological crises, founded also on economic theories and misconceived choices. The implication is a search for alternatives through an ontological-evolutionary-institutional approach and empirical investigations.
 The search for political ‘normative economics’, entity economics, accounting and information science copes with social and ecological-environmental problems, and systems science; it is necessary to keep always in mind these interactions for fully understand and correctly interpret the present ‘social-economic reality’.
 The problem concerning environmental decisions goes beyond ontology and belongs to ethics. It must underline the debates on ‘evolutionary ethics’, not only related with ‘environmental and ecological economics’, the management of environment and reporting, but also with ‘evolutionary ontology’; the new perspective affirms that ‘existence’, for instance, of a moral behavioral attitude, can reveal itself as a ‘norm’ thus relating ethics to ontology.
 General economists, entity economics theorists, as well as accountants and information scientists should be familiar with the potentials and limits of ‘ontology’, also for the ongoing expansion of computerization of scientific research in most of the scientific domains. The renewed interest, particularly in ontology, arouse specifically from systems scientists in constructing a wide variety of artificial intelligent systems. For its analysis, the study has been structured into two periods of time: until the middle of the 20th century and from that moment on. The paper ends by showing the new developments in information systems and their ontological approach

Attenuation of the contribution of groundwater to a wetland caused by groundwater overexploitation

AbstractThe continuous exploitation of groundwater has made wetland degradation an ecological and geological environmental problem that cannot be ignored and has had impacts on the ecological environment and human production and life. In this study, Modflow was used to simulate the wetland‐aquifer interaction during the multiyear pumping process, establish a quasi‐ideal model of wetlands based on the actual area of the Baiyangdian Basin, simulate the relationship of water quantity change between wetlands and piedmont plain aquifers during groundwater exploitation and its natural recovery process, and quantify the attenuation of the contribution of groundwater to wetlands caused by groundwater overexploitation. Two components of wetland water reduction are explored through the simulation and calculation of wetland‐aquifer interactions under different exploitation conditions. The results show that in the process of groundwater exploitation, the impact of groundwater overexploitation on wetland degradation is mainly divided into two parts: one is the reduced base flow from the piedmont plain to the wetland, and the other is the induced infiltration caused by the reverse recharge of groundwater from the wetland due to the pumping effect. Compared with the wetland water reduction during the pumping process, the process of water recovery during the natural recovery process is much slower, which indicates the residual effect of exploitation will continue for a long time. The findings provide a scientific reference for the management of water resources in wetland areas.

Enhanced removal of estrogens from simulated wastewater by biochar supported nanoscale zero-valent iron: performance and mechanism

The intensification of estrogen non-point source pollution has drawn global attention due to their contribution to ecological environment problems worldwide, and it is critical to develop effective, economic and eco-friendly methods for reducing estrogens pollution. To address the agglomeration and oxidation of nano zero-valent iron (nZVI), biochar-nanoscale zero-valent iron composite (nZVI-biochar) could be a feasible choice for estrogens removal. This study summarized biochar and nZVI-biochar preparation, characterization, and unusual applications for estrone (E1), 17β-estradiol (E2), and estriol (E3) removal. The properties of biochar and nZVI-biochar in characterization, effects of influencing factors on the removal efficiency, adsorption kinetics, isotherm and thermodynamics were investigated. The experiment results showed that nZVI-biochar exhibited the superior removal performance for estrogens pollutants compared to biochar. Based on the quasi-second-order model, estrogens adsorption kinetics were observed, which supported the mechanism that chemical and physical adsorption existed simultaneously on estrogens removal. The adsorption isotherm of estrogens could be well presented by the Freundlich model and thermodynamics studies explained that nZVI-biochar could spontaneously remove estrogens pollutants and the main mechanisms involved π-π interaction, hydrophobic interaction, hydrogen bonding and degradation through ring rupture. The products analyzed by GC–MS showed that estrogens degradation was primarily attributed to the benzene ring broken, and Fe3+ promoted the production of free radicals, which further proved that nZVI-biochar had the excellent adsorption performances. Generally, nZVI-biochar could be employed as a potential material for removing estrogens from wastewater.Graphical

The Three Dimensions of Buddhist Ecological Ethics Wisdom

Buddhist ecological ethics wisdom is an important ideological resource for dealing with contemporary ecological environmental problems. Compared with Western eco-cultural pluralism and local Confucian and Taoist eco-ethical thinking, Buddhist ecological ethics wisdom is unique and profound regarding theoretical roots and core principles. In-depth study and grasp of the three major dimensions of Buddhist ecological ethics wisdom, namely, cherishing nature, equal mercy, and purifying minds and lands, will make it possible to face the ecological dilemmas in reality and realize the creative transformation and innovative development of its values.

The Dilemma of Environmental Governance in Urban-Rural Fringe and its Solution: A Case Study of Lizhou District, Sichuan Province

The rapid development of China's cities and countryside has led to the construction of the urban-rural fringe. However, due to its location in the transition zone between urban and rural areas, it is greatly influenced by the inherent ecological model of rural areas, weak environmental awareness, lack of effective behavior management, and imperfect laws and regulations, which lead to increasingly prominent ecological environmental problems in the urban-rural fringe. It is urgent to build a beautiful environment, increase the happiness of residents in the urban-rural fringe, and carry out environmental governance in the urban-rural fringe. Through case reduction and in-depth interviews, this paper discusses the environmental particularity, environmental pollution, and collaborative governance of the urban-rural fringe Given its internal mechanism and multi-core environmental governance, the summary and optimization are summarized, and many problems of its predicament and cracking ways still need to be solved by the government. It is hoped that environmental governance of the urban and rural combined part of Sichuan Province can bring enlightenment to environmental governance of the urban and rural combined part of China.

Differential response of the soil nutrients, soil bacterial community structure and metabolic functions to different risk areas in Lead-Zine tailings.

Rapid growth in the mining industry has brought about a large formation of tailings, which result in serious destruction of the ecological environment and severe soil pollution problems. This study assesses soil nutrients, soil bacterial community and soil microbes' metabolic function in heavily polluted areas (W1), moderately polluted areas (W2), lightly polluted areas (W3) and clean areas (CK) using 16S Illumina sequencing. The results of this study showed that compared with CK, a severe loss of soil nutrients and richness of OTUs (Chao1 and ACE indices) were observed with the aggravated pollution of tailings. The Chao1 and ACE indices in the W1 group decreased significantly by 15.53 and 16.03%, respectively, (p < 0.01). Besides, the relative abundance of Actinobacteria and Proteobacteria was high whereas and relative abundance of Chloroflexi in the polluted areas. Among them, W1 groups increased significantly the relative abundance of Actinobacteria and decreased significantly the relative abundance of Chloroflexi, these can be used as indicator phyla for changes in soil community structures under polluted stress. Tax4 Fun analysis showed that W1 groups affected the soil bacterial community and altered the primary types of biological metabolism in polluted areas. Tailings have adverse impacts on soil bacterial community and metabolic functions, and the deterioration in soil quality is dependent on the levels of tailings pollution. Cumulatively, this study provides valuable information on the bacterial community structure and metabolic functions in the tailing polluted soil.

Synergistic effect of red mud, desulfurized gypsum and fly ash in cementitious materials: Mechanical performances and microstructure

The use of industrial solid waste to prepare cementitious materials can not only solve the pollution problem of ecological environment, but also help carbon emission reduction and sustainable development. In this work, typical alkaline solid waste - red mud (RM), sulfate solid waste - desulfurization gypsum (DG) and silicon-aluminum character solid waste - fly ash (FA) were used to prepare cementitious materials. The influence of synergistic effect of RM-DG-FA on the mechanical performances and hydration products of cementitious materials were systematically investigated. The hydration products were characterized and analyzed by XRD, TG, FTIR, MIP and SEM-EDS. It was found that the mechanical performances of cementitious materials were significantly improved under the synergistic effect of three kinds of solid wastes. When the content of the three solid wastes was 50%, the compressive strength of the cementitious materials at 28 d was 50.60 MPa, and the mechanical performances at each age were higher than the # 42.5 Portland cement standard. The microstructure results showed that under the synergistic action of alkali and sulfate, the active silicon and aluminum substances in RM and FA can quickly participate in the reaction, which makes the hydration degree of cementitious materials can move to the reaction direction with higher polymerization degree. The hydration products mainly included ettringite, C-S-H and C(N)-A-S-H gel. A large amount of gel and ettringite grew alternately, which reduced the porosity and formed a dense structure of the cementitious materials matrix, and its mechanical performances were improved. The leaching results showed that the synergistic effect also improved the solidification ability of the cementitious materials to Na+. In this work, the synergistic effect of RM-DG-FA significantly increased the utilization of solid wastes and the performances of cementitious materials. The research results provided a scientific basis for improving the utilization rate of alkaline solid wastes, sulfate solid wastes and silicon-aluminum character solid wastes and their collaborative utilization as building materials.