Deciphering the key factors affecting pesticide residue risk in vegetable ecosystem.

Soil contamination, particularly from pesticide residues, presents a significant challenge to the sustainable development of agricultural ecosystems. Identifying the key factors influencing soil pesticide residue risk and implementing effective measures to mitigate their risks at the source are essential. Here, we collected soil samples and conducted a comprehensive survey among local farmers in the Three Gorges Reserve Area, a major agricultural production region in Southwest China. Subsequently, employing a dual analytical approach combining structural equation modeling (SEM) and random forest modeling (RFM), we examined the effects of various factors on pesticide residue accumulation in vegetable ecosystems. Our SEM analysis revealed that soil characteristics (path coefficient 0.85) and cultivation factor (path coefficient 0.84) had the most significant effect on pesticide residue risk, while the farmer factors indirectly influenced pesticide residues by impacting both cultivation factors and soil characteristics. Further exploration using RFM identified the three most influential factors contributing to pesticide residue risk as cation exchange capacity (CEC) (account for 18.84%), cultivation area (account for 14.12%), and clay content (account for 13.01%). Based on these findings, we carried out experimental trials utilizing Integrated Pest Management (IPM) technology, resulting in a significant reduction in soil pesticide residues and notable improvements in crop yields. Therefore, it is recommended that governmental efforts should prioritize enhanced training for vegetable farmers, promotion of eco-friendly plant protection methods, and regulation of agricultural environments to ensure sustainable development.

Risk assessment of exposure to 12 kinds of mycotoxins through consumption of Pericarpium Citri Reticulatae collected from Three Gorges Reservoir area of China.

A method for simultaneous determination of 12 mycotoxins in Pericarpium Citri Reticulataeby HPLC-MS/MS was established to analyze the residues of mycotoxins, inwhich from Three Gorges Reservoir area of China, including AFB1, AFB2, AFG1, AFG2, T-2, FB1, FB2, FB3, ZEN, OTA, OTB and DON.In addition, a probabilistic assessment model based on Monte Carlo simulation method was established in combination with pollution data, and the health risk assessment was carried out by the exposure limit method (MOE).The results showed that the method with strong specificity, good linearity and accurate recovery was established and could be used for the determination of 12 mycotoxins in Pericarpium Citri Reticulatae.In general, the total pollution rate of different degrees of pollution in the 36 batches of Pericarpium Citri Reticulatae sampleswas 75 %. It should be noted thatthe proportion of positive samplescontaminated by one toxin was the highest (59.26 %), and the detection rate of FB3 in Pericarpium Citri Reticulataewas the highest (66.67%), followed by AFG1 (44.44 %), indicating that the medicinal material polluted by AFG1 and AFB3 alone or simultaneously was more serious. Specifically, the detection rate of mycotoxins in Chongqing was the highest (92.31%) on account of the high temperature and humidity in Chongqing, followed by Southeast of Sichuan (83.33%) and West of Hubei (45.45%).On the other hand, the MOE of AFB1 and AFB2 calculated were both greater than 10000, indicating that the health risk of AFB1 and AFB2 exposure caused by taking Pericarpium Citri Reticulatae was low, but the risk of high intake population was higher than that of conventional intake population, which needed to be paid attention to. This study can provide a reference for the safety assessment of clinical medication of Pericarpium Citri Reticulatae inThree Gorges Reservoir area.

Analyzing spatio-temporal changes and trade-offs/synergies of gross ecosystem product based on water-energy-food nexus.

The value of the ecosystem's ultimate goods and services for human welfare and long-term economic and social development is known as the gross ecosystem product (GEP). For the study of GEP accounting, the suggested water-energy-food (WEF) nexus offers a fresh viewpoint. This work aims to build a GEP accounting index system based on WEF, investigate its spatio-temporal evolution characteristics, and assess trade-offs and synergies between and within the water, energy, and food subsystems. Using the Three Gorges Reservoir area (TGRA) as an illustration, the findings revealed that, firstly, the comprehensive benefit of GEP based on WEF showed an upward trend in TGRA. Still, it was worth noting that the total production of the food ecosystem decreased. Secondly, the GEP based on WEF in five periods showed a spatial pattern of "high east and west, low middle." Thirdly, the Pearson correlation coefficient indicated that the GEP trade-off relationships based on WEF were dominant in TGRA, with the strongest trade-offs between AQV, SCV, APV, and LEV. In addition, in bivariate local spatial autocorrelation, the value of the six ecosystem service function relationships was dominated by the trade-off relationship, and the distribution of trade-offs and synergies showed significant heterogeneity at the county scale in the TGRA. Finally, hot spot analysis showed that the hot spots of the gross water and energy ecosystem products were scattered in the tail area of the study area. In contrast, the hot spots of the gross food ecosystem product were concentrated in the belly region. The findings of this study provided a basis for the scientific formulation of territorial spatial pattern optimization for water, energy, and agricultural resources in the TGRA and can more accurately reflect the status of the ecological environment and changes of WEF over time. Moreover, this paper also gives full play to the growth advantages of shipping and aquatic products, implements effective soil erosion prevention and control measures, and establishes water-saving mechanisms and other measures in terms of water resources. Subregional plans for industrial structure and strengthening of waste gas and wastewater treatment facilities regarding energy resources are developed. Implement the cultivated land protection system and promote the superiority of crop varieties and other measures in terms of food resources.

Effects of the catastrophic 2020 Yangtze River seasonal floods on microcystins and environmental conditions in Three Gorges Reservoir Area, China.

Introduction: During July and August 2020, Three Gorges Reservoir Area (TGRA) suffered from catastrophic seasonal floods. Floods changed environmental conditions and caused increase in concentration of microcystins (MCs) which is a common and potent cyanotoxin. However, the effects and seasonal variations of MCs, cyanobacteria, and environmental conditions in TGRA after the 2020 Yangtze River extreme seasonal floods remain largely unclear, and relevant studies are lacking in the literature. Methods: A total of 12 representative sampling sites were selected to perform concentration measurement of relevant water quality objectives and MCs in the representative area of the TGRA. The sampling period was from July 2020 to October 2021, which included the flood period. Organic membrane filters were used to perform the DNA extraction and analyses of the 16S rRNA microbiome sequencing data. Results: Results showed the seasonal floods result in significant increases in the mean values of microcystin-RR (MCRR), microcystin-YR (MCYR), and microcystin-LR (MCLR) concentration and some water quality objectives (i.e., turbidity) in the hinterland of TGRA compared with that in non-flood periods (p < 0.05). The mean values of some water quality objectives (i.e., total nitrogen (TN), total phosphorus (TP), total dissolved phosphorus (TDP), and turbidity), MC concentration (i.e., MCRR, MCYR, and MCLR), and cyanobacteria abundance (i.e., Cyanobium_PCC-6307 and Planktothrix_NIVA-CYA_15) displayed clear tendency of increasing in summer and autumn and decreasing in winter and spring in the hinterland of TGRA. Discussions: The results suggest that seasonal floods lead to changes in MC concentration and environmental conditions in the hinterland of TGRA. Moreover, the increase in temperature leads to changes in water quality objectives, which may cause water eutrophication. In turn, water eutrophication results in the increase in cyanobacteria abundance and MC concentration. In particular, the increased MC concentration may further contribute to adverse effects on human health.

Temporal profiling of sediment microbial communities in the Three Gorges Reservoir Area discovered time-dissimilarity patterns and multiple stable states.

Microbial communities play vital roles in cycling nutrients and maintaining water quality in aquatic ecosystems. To better understand the dynamics of microbial communities and to pave way to effective ecological remediation, it's essential to reveal the temporal patterns of the communities and to identify their states. However, research exploring the dynamic changes of microbial communities needs a large amount of time-series data, which could be an extravagant requirement for a single study. In this research, we overcame this challenge by conducting a meta-analysis of years of accumulations of 16S rRNA high-throughput sequencing data from the Three Gorges Reservoir Area (TGRA), an ecological and environmental hotspot. For better understanding the microbial communities time-dissimilarity dynamics, three microbial communities time-dissimilarity patterns were hypothesized, and the linear pattern in the TGRA was validated. In addition, to explore the stability of microbial communities in the TGRA, two alternative stable states were revealed, and their differences in community richness, alpha diversity indices, community composition, ecological network topological properties, and metabolic functions were demonstrated. In short, two states of microbial communities showed distinct richness and alpha diversity indices, and the communities in one state were more dominated by Halomonas and Nitrosopumilaceae genera, facilitating nitrogen cycling metabolic processes; whilst the main genera of the other state were Bathyarchaeia and Methanosaeta, which favored methane-related metabolism. Moreover, different studies and environmental differences between mainstream and tributaries were attributed as the potential inducing factors of the state division. Our study provides a comprehensive insight into the dynamics and stability of microbial communities in the TGRA, and a reference for future studies on microbial community dynamics.

A new assessment method for water environment safety and its application.

The Three Gorges Reservoir area is recognized by its vast size, dense population, bustling economic and social activities along its banks, and by the significant volume of waterway traffic. These factors make it with a high risk of water pollution accidents, posing a serious threat to water environmental safety. Therefore, it is imperative to conduct a water environmental safety assessment in this region to ensure the safety of the water environment. In the present work, the Driving-Pressure-State-Impact-Response-Risk Water Environmental Safety model was proposed, and a comprehensive water environmental safety assessment system was established. The Water Environment Safety Index was introduced to measure the degree of water environment safety. This model synthesized multiple factors and their interrelationships, enabling a more accurate assessment of water environment safety. By adopting scientifically rigorous evaluation criteria, this assessment method enhanced the reliability and credibility of the results obtained. The water environment safety in the 22 counties and districts of the Three Gorges Reservoir area of Chongqing region from 2017 to 2021 was assessed in terms of temporal changes and spatial differentiation. In general, the overall water environment safety situation in the Three Gorges Reservoir area of Chongqing region is relatively safe, but a few counties/districts (such as Wanzhou District, Jiangjin District, etc.) are still in Warning. Spatially, the water environmental safety condition was relatively better in the northeast compared to the southwest. The main factors threatening water environment safety include: 1) the consequence of the Three Gorges Project, 2) severe soil erosion, 3) industrial, agricultural, and domestic pollution, and 4) frequent water pollution accidents. The present work provided a new method for conducting water environment safety assessments, which is expected to positively contribute to further research in this field.

Dynamic landslide susceptibility mapping based on the PS-InSAR deformation intensity.

In order to meet the needs of refined landslide risk management, the extended correlation framework of dynamic susceptibility modeling desiderates to be further explored. This work considered the Wanzhou channel of the Three Gorges Reservoir Area as the experimental site, with a transportation channel with significant economic value to carry out innovative research in two stages. (i) Five machine learning models logistic regression (LR), multilayer perceptron neural network (MLPNN), support vector machine (SVM), random forest (RF), and decision tree (DT) were used to explore landslide susceptibility distribution based on detailed landslide boundaries. (ii) Based on the PS-InSAR technology, the dynamic factor of deformation intensity was obtained. Subsequently, the dynamic factor was combined with proposed static factors (topography conditions, geological conditions, hydrological conditions, and human activities) to generate dynamic landslide susceptibility mapping (DLSM). The receiver operating characteristic (ROC) curve, accuracy, precision, recall, and F1 score were proposed as evaluation metrics. Compared with ignoring the dynamic factor, the predictive accuracy of some models was further improved when considering the dynamic factor. Especially the DT model, the area under the curve of ROC (AUC) value increased by 2%, and obtained the highest AUC value (93.1%). The susceptibility results of introducing the dynamic factor are more in line with the spatial distribution of actual landslides. The research framework proposed in this study has important reference significance for the dynamic management and prevention of landslide disasters in the study area.

Disentangling the role of environmental filtering and biotic resistance on alien invasions in a reservoir area.

Large-scale water conservancy projects benefit human life but have modified the landscape and provided opportunities for alien plant invasions. Understanding the environmental (e.g., climate), human-related (e.g., population density, proximity to human activities), and biotic (e.g., native plant, community structure) factors driving invasions is essential in the management of alien plants and biodiversity conservation in areas with intense human pressure. To this end, we investigated the spatial patterns of alien plant species distribution in the Three Gorges Reservoir Area (TGRA) of China and distinguished the role of the external environment and community characteristics in determining the occurrence of alien plants with differing levels of known invasion impacts in China using random forest analyses and structural equation models. A total of 102 alien plant species belonging to 30 families and 67 genera were recorded, the majority being annual and biennial herbs (65.7%). The results showed a negative diversity-invasibility relationship and supported the biotic resistance hypothesis. Moreover, percentage coverage of native plants was found to interact with native species richness and had a predominant role in resisting alien plant species. We found alien dominance was mainly the result of disturbance (e.g., changes in hydrological regime), which drove native plant loss. Our results also demonstrated that disturbance and temperature were more important for the occurrence of malignant invaders than all alien plants. Overall, our study highlights the importance of restoring diverse and productive native communities in resistance to invasion.

A novel evaluation system of green development level in the Three Gorges Reservoir Area and its spatial-temporal pattern.

Evaluating the green development level (GDL) of a region will accelerate its economic transformation and promote ecological civilization. From the perspective of complex system, this study explores the green development level (GDL) of the Three Gorges Reservoir Area (TGRA) by constructing a novel and ecology-oriented evaluation system. The system is three-dimensional including indicators of environmental protection and utilization, green economy development, social harmony and prosperity. Resource elements are highly valued; inclusive society is fully considered. Overall entropy method and expert scoring method are integrated to assess the GDL of 26 regions in the TGRA from 2000 to 2020; the temporal and spatial characteristics of the GDL are examined through exploratory spatial data analysis (ESDA). The results show that (1) the GDL of the TGRA is at a medium level with the score fluctuating from 0.3 to 0.4 and the ecological protection with weight of 0.37 contributes greatly to the GDL. (2) Despite the high degree of coupling coordination, the complex ecosystem in the TGRA remains at a low level of coordinated development. (3) The GDL in the middle part of the TGRA is the highest, followed by the upper part and the lower part, and the gap is narrowing. (4) The global spatial correlation of the GDL is not obvious. The spatial spillover effect is not significant and clusters only appear in the upper part and the lower part. Finally, some reasonable suggestions are put forward for improving the GDL.

[Biochar or Straw Substituting Chemical Fertilizer Increase the Risk of Phosphorus Loss in Subsurface Runoff in Sloping Farmland].

The purple soil slope farmland is an important agricultural land in southwest China but is also one of the main sources of agricultural non-point source pollution in the Three Gorges Reservoir area. Taking reasonable measures to control the loss of soil nutrients is of great significance to the treatment of non-point source pollution in the region. Here, a three-year (2018-2020) field runoff experiment was conducted to monitor and evaluate the phosphorus (P) loss in sloping farmland via surface runoff (i.e., surface flow, 0-20 cm) and subsurface runoff (i.e., subsurface flow, 20-60 cm), with five treatments including no fertilization (CK), conventional fertilization (CF), optimal fertilization (OF), biochar combined with 85% of OF (BF), and straw combined with 85% of OF (SF). The results showed that fertilization application reduced the sediment yields and surface runoff flux but increased the subsurface runoff flux. The total loss flux of phosphate (PO3-4-P), total phosphorus (TP), and particulate phosphorus (PP) in surface flow were the highest in the BF treatment and the lowest in the SF treatment. All fertilization applications increased the P loss fluxes in subsurface flow relative to that in CK. The highest PO3-4-P and TP loss flux in subsurface flow was found in the BF (213.88 g·hm-2 and 694.54 g·hm-2, respectively) treatment, followed by that in the OF and SF treatments. Redundancy analysis (RDA) results showed that surface runoff flux and biochar application were the main factors contributing to increased P loss in surface flow, and subsurface runoff flux was the main factor contributing to increased P loss in subsurface flow. In summary, the SF treatment reduced the amount of sediment yield and surface runoff flux in sloping farmland of purple soil and was the most effective for controlling P loss, whereas the risk of subsurface runoff flux requires further attention.

Regional climate change and possible causes over the Three Gorges Reservoir Area.

The Three Gorges Project, the largest hydroelectric project in the world, has attracted widespread attention regarding its impact on regional climate. However, existing studies on the climate effects of the Three Gorges Project construction are not sufficient due to limited data accumulation. In this study, we analyzed the annual and seasonal trend changes in temperature, precipitation, and humidity over the Three Gorges Reservoir Area (TGRA) based on long-term meteorological stations data, remote sensing data, and reanalysis products. Observation minus reanalysis method (OMR) was used to reveal possible impacts of land cover changes on climate changes. Major results indicated that the TGRA experienced an overall warming trend for both annual and seasonal variations, with greater rising trends in the upstream. Except for autumn, the relative humidity of most regions mainly showed significant downward trends, indicating an overall drying trend in the TGRA. There was insignificant change in total precipitation and precipitable water vapor, with the largest variation observed during the summer. Although there were small differences among these datasets, their results of climate changes showed good consistency overall. In addition, the results of OMR indicated that land cover changes mainly had a warming and drying effect on the middle and upper reaches, and a cooling and moistening effect on the lower reaches of the TGRA. This may be due to the impact of land cover changes on the surface energy balance, thus affected temperature and humidity. The study has important reference value for understanding the climate changes in the TGRA and the climate effects brought about by large-scale engineering construction.

[Characteristics and Risk Evaluation of Heavy Metal Contamination in Paddy Soils in the Three Gorges Reservoir Area].

Soil Cd, Hg, Pb, As, Cr, Cu, Zn, and Ni of 12 districts in the Three Gorges Reservoir area (Chongqing section) were analyzed, and different evaluation methods were used to assess the degree of contamination, potential ecological risk, and human health risk of soil heavy metals in paddy soils. The results showed that the average values of all heavy metals except Cr in paddy soils in the Three Gorges Reservoir area exceeded the background values of soils in the Three Gorges Reservoir area, and the contents of Cd, Cu, and Ni in 12.32%, 4.35%, and 2.54% of the soil samples exceeded the screening values, respectively. The variation coefficients of the eight heavy metals were 29.08%-56.43%, which belonged to the medium and above-intensity variation levels and were influenced by anthropogenic activities. The eight heavy metals were contaminated in the soil, and 16.30%, 6.52%, and 2.90% of the soil Cd, Hg, and Pb were heavily contaminated. At the same time, the potential ecological risk of soil Hg and Cd were in the medium risk level on the whole. Wuxi County and Wushan County had relatively high pollution levels among the 12 districts, the Nemerow pollution index showed a moderate pollution level, and the comprehensive potential ecological risks were also at a moderate ecological hazard level. The results of the health risk evaluation showed that hand-mouth intake was the main exposure path of non-carcinogenic risk and carcinogenic risk. Soil heavy metals presented no non-carcinogenic risk for adults (HI<1), but 12.68% of the sites had non-carcinogenic risk for children (HI>1). As and Cr were the main influencing factors for non-carcinogenic and carcinogenic risks in the study area, and their total contributions to non-carcinogenic and carcinogenic risks were more than 75% and 95%, respectively, which was cause for concern.

Occurrence profiling and environmental risk assessment of veterinary antibiotics in vegetable soils at Chongqing region, China.

Veterinary antibiotics (VAs) are emerging contaminants in soils as they may pose high risks to the ecosystem and human health. Identifying VAs accumulation in soils is essential for assessing their potential risks. Therefore, we investigated the distribution of VAs in soils from vegetable fields and evaluated their potential ecological and antimicrobial resistance risks in the Chongqing region of the Three Gorges Reservoir area, China. Results indicated that twenty-six species of VAs, including nine sulfonamides (SAs), seven quinolones (QNs), four tetracyclines (TCs), four macrolides (MLs), and two other species of VAs were detected in soils, with their accumulative levels ranging from 1.4 to 3145.7 µg kg-1. TCs and QNs were the dominant VAs species in soils with high detection frequencies (100% TCs and 80.6% for QNs) and accumulative concentration (up to 1195 µg kg-1 for TCs and up to 485 µg kg-1 for QNs). Risk assessment indices showed that VAs (specifically SAs, TCs, and QNs) in most vegetable soils would pose a medium to high risk to the ecosystem and antimicrobial resistance. Mixture of VAs posed a higher risk to soil organisms, antimicrobial resistance, and plants than to aquatic organisms. Modeling analysis indicated that socioeconomic conditions, farmers' education levels, agricultural practices, and soil properties were the main factors governing VAs accumulation and environmental risks. Farmers with a high educational level owned large-scale farms and were more willing to use organic fertilizers for vegetable production, which eventually led to high VAs accumulation in vegetable soil. These findings would provide a reference for sustainable agricultural and environmental production under the current scenario of chemical fertilizer substitution by organic products and green agricultural development.

Identifying the critical areas and primary sources for agricultural non-point source pollution management of an emigrant town within the Three Gorges reservoir area.

Agricultural non-point source pollution is threatening water environmental health of the Three Gorges reservoir. However, current studies for precision management of the agricultural non-point source pollution within this area are still limited. The objective of this study was identifying the critical areas and primary sources of agricultural non-point source pollution for precision management. Firstly, the inventory analysis approach was used to estimate the discharge amount of total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD) from farmland fertilizer, crop residues, livestock breeding, and daily activities. Afterwards, the deviation standardization method was applied to evaluate the emission intensity of TN, TP, and COD, as well as calculating the comprehensive pollution index (CPI) of each village, based on which the critical areas for agricultural non-point source pollution management could be distinguished. Moreover, the equivalence pollution load method was conducted to identify the primary pollution sources within each critical zone. The above methods were implemented to an emigrant town within the Three Gorges reservoir area named Gufu. Results showed that agricultural non-point source pollution in Gufu town has been alleviated to a certain extent since 2016. Nevertheless, in four areas of the town (i.e., Longzhu, Fuzi, Shendu, and Maicang), the agricultural non-point source pollution still deserved attention and improvement. For the mentioned critical areas, farmland fertilizer and livestock breeding were the primary sources causing agricultural non-point source pollution. The emission amount of TN and TP from farmland fertilizer accounted for 60% and 48% of the total, respectively. And those from livestock breeding were 29% and 46%. Our research could provide definite targets to relieve agricultural non-point source pollution, which had great significance to protect water environment while coordinating regional economic growth after emigrant resettlement.

Findings on agricultural cleaner production in the three Gorges Reservoir Area.

The 'rural revitalization strategy' is important to achieve sustainable development in the Three Gorges Reservoir Area (TGRA), the largest reservoir in China, located in the poverty alleviation region of the Qinling-Daba mountains, and characterized as mountainous and hilly dominated by backwards resettlements. Pig farming around the reservoir area is a key industry, accounting for 0.90% of the arable land area in the country, while the annual pig market represents a 1.37% share of the national figure. Here, 12 study sites were investigated on-site for understanding agricultural green development in the TGRA. We found two main prevailing models: one of ecological circulation (EC), based on animal husbandry and recycling. Of the 12 site, six cases of the ecological circulation model relied on pig husbandry, combined with cropping (grains/fruits/vegetables) by eco-industrial chains, such as pig-biogas-fruit (grain/vegetables), to prevent environmental pollution, while promoting agricultural economic growth by recycling fecal residues and wastewater (FSW) from pig-husbandry facilities to the fields. Our analysis predicted that a farm holding 10,000 pigs may save inorganic nitrogen and phosphorus fertilizers by as much as 74.36 and 11.15 ton·a-1, respectively. On the other hand, five cases of ecological models oriented towards agritourism provided tourists with high-quality ecological products while coordinating environment protection with economic development. In addition, 11 research points applied water and fertilizer integration system for the purpose of saving water. However, lack of sufficient supporting arable land made intensive pig farming a risk of ecological degradation. Green control technologies are rarely used leading to an increase in the type and amount of pesticides. Our study has theoretical and practical significance for decision-makers to promote agricultural cleaner production (ACP).

[Pollution Characteristics and Source Apportionment of Heavy Metals in Vegetable Field in the Three Gorges Reservoir Area (Chongqing Section)].

To explore the pollution characteristics, ecological risks, and sources of heavy metals, soil surface samples of vegetable fields in 14 typical districts of the Three Gorges Reservoir area (Chongqing section) were collected in October 2021. The contents of seven types of heavy metals (As, Cd, Cr, Cu, Ni, Pb, and Zn) were analyzed. Based on the single-factor pollution index, the Nemerow integrated pollution index and potential ecological risk coefficient of heavy metals were evaluated. Additionally, the effects of different planting years and methods (open-field and greenhouse planting) on soil heavy metal accumulation were analyzed. The results indicated that the mean concentrations of heavy metals in vegetable soils in the area were lower than the national risk screening values for soil contamination of agricultural land (GB 15618-2018) but higher than their background values in Chongqing. According to the single-factor pollution index method, Pb, Zn, Cu, and Cd showed negligible slight hazards. The Nemerow pollution index showed that the study area was at a slight hazard level, and the main factors were Ni and Cd. Heavy metal pollution was found in 91.4% of the soil samples (PN>1) with different degrees, and 9.19% of them were severely polluted. The potential ecological risk coefficient showed that the vegetable lands were polluted slightly, and 9.77% of soil samples polluted by Cd were at moderate ecological risk. According to cluster analysis, the sources of Cd-Cu-Pb-Zn and As-Cr-Ni were similar. The content of heavy metals in the open field and greenhouse showed an increasing trend with the increase in planting years, and the content of heavy metals in greenhouse soil were generally higher than that in open field soil.

[Structural Diversity and Its Temporal Variation in the Soil Bacterial Community Under Plantations of Taxodium distichum in the Riparian Zone of the Three Gorges Reservoir Area].

The riparian zone supports important ecological functions and acts as an ecotone connecting terrestrial and aquatic areas. Soil microbes under the revegetation of woody species are crucial to the biogeochemical cycle of nutrients. Here, soil samples were collected to examine the soil microbes during different emergence phases in 2019 (May:T1, July:T2, and September:T3) in the riparian zone of the Three Gorges Reservoir, China. The variations in the bacterial community were evaluated using high-throughput sequencing. The results showed that:during the emergence phases, soil properties such as pH value (pH), ammonium nitrogen (NH4+-N), and nitrate-nitrogen (NO3--N) and soil enzymes changed significantly(P<0.05), and soil bacterial α diversity also changed with time. Except for the Chao1 index, the richness of rhizosphere soil bacteria showed T1>T2>T3, whereas the α diversity of non-rhizosphere soil bacteria showed T3>T1>T2. The redundancy analysis (RDA) test implied that soil urease, NH4+-N, pH, and NO3--N were the key factors structuring the microbial community. Proteobacteria and Acidobacteria were the two dominant components among the 60 phyla that were detected in the soil. Based on phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt2) prediction, metabolism was the basic function of soil bacterial communities of Taxodium distichum; in the secondary functional layer, the metabolic pathways related to carbon, nitrogen, and phosphorus mainly included amino acid metabolism, carbohydrate metabolism, lipid compound metabolism, and energy metabolism, and the relative abundance of each metabolic function had a certain time difference in different periods. These findings could help us better understand how soil microbes change after restoring vegetation in the Three Gorges Reservoir area.

Output characteristics and driving factors of non-point source nitrogen (N) and phosphorus (P) in the Three Gorges reservoir area (TGRA) based on migration process: 1995-2020.

Although physical models at present have made important achievements in the assessment of non-point source pollution (NPSP), the requirement for large volumes of data and their accuracy limit their application. Therefore, constructing a scientific evaluation model of NPS nitrogen (N) and phosphorus (P) output is of great significance for the identification of N and P sources as well as pollution prevention and control in the basin. We considered runoff, leaching and landscape interception conditions, and constructed an input-migration-output (IMO) model based on the classic export coefficient model (ECM), and identified the main driving factors of NPSP using geographical detector (GD) in Three Gorges Reservoir area (TGRA). The results showed that, compared with the traditional export coefficient model, the prediction accuracy of the improved model for total nitrogen (TN) and total phosphorus (TP) increased by 15.46 % and 20.17 % respectively, and the error rates with the measured data were 9.43 % and 10.62 %. It was found that the total input volume of TN in the TGRA had declined from 58.16 × 104 t to 48.37 × 104 t, while the TP input volume increased from 2.76 × 104 t to 4.11 × 104 t, and then decreased to 4.01 × 104 t. In addition Pengxi River, Huangjin River and the northern part of Qi River were high value areas of NPSP input and output, but the range of high value areas of migration factors has narrowed. Pig breeding, rural population and dry land area were the main driving factors of N and P export. The IMO model can effectively improve prediction accuracy, and has significant implications for the prevention and control of NPSP.

Spatio-Temporal Evolution and Influencing Factors of Ecological Well-Being Performance from the Perspective of Strong Sustainability: A Case Study of the Three Gorges Reservoir Area, China.

The concept of strong sustainability suggests that natural capital is irreplaceable and emphasizes that human natural consumption cannot exceed the carrying capacity of the ecological environment. In the realistic context of tightening resource constraints and ecological degradation, how to explore the optimal economic and well-being output under certain ecological constraints has become an important topic in sustainability research. Ecological well-being performance (EWP) can comprehensively reflect the efficiency of natural resources and ecological inputs into the well-being level and has become an important tool for sustainable development research. Based on strong sustainability, this paper constructs an EWP evaluation index system. It decomposes EWP into two stages: ecological economy and economic well-being, which opens the "black box" of the ecological well-being conversion process. PCA-DEA, the network super-efficiency Epsilon-based measure (Network SEBM) model, and Geodetector are used to dynamically measure the EWP in the Three Gorges Reservoir Area (TGRA) from 2010 to 2020 and analyze its spatial and temporal characteristics and influencing factors. The results show that (1) temporally, the EWP in the TGRA shows an increasing trend from 2010 to 2020, but the overall level is low. Spatially, it shows a high pattern in the east and low in the west, and spatial differences are gradually decreasing; (2) ecological economic efficiency is significantly lower than economic well-being efficiency, and ecological economic efficiency is the main reason limiting the improvement in EWP in the TGRA. The ecological well-being situation of the TGRA is not optimistic; (3) there is an overall problem of excessive ecological input and insufficient per-capita GDP and well-being output in the TGRA, and decisions should be made according to local conditions; (4) the level of economic development has an EWP level that plays a dominant role and also has a greater relationship with the policy system, socioeconomic conditions, and natural environment.

Degradation of Typical Reverse Sand-Mudstone Interbedded Bank Slope Based on Multi-Source Field Experiments.

The bank slopes in the Three Gorges Reservoir area (TGRA) have experienced obvious deterioration under the action of the periodic fluctuations in the reservoir water level. Generally, laboratory tests have been used to reveal the evolution trend of the slope banks. However, this method has a certain degree of cross-scale problem, especially for the mechanical state in a complex environment. Therefore, in this study, we took the Yangjiaping bank slope in the TGRA as an example and proposed a comprehensive on-site detection method to further reveal the rock mass degradation phenomenon of this typical reverse sand-mudstone interbedded bank slope. Specifically, multi-scale laser scanning, cross-hole acoustic wave detection, and inclination measurements were performed to analyze the fractures, quality, and deformation of rocky banks. The results showed that the deterioration of the bank slope manifested as the expansion, deepening, and widening of the cracks, as well as the peeling off and loosening of rocky banks. Large-scale laser scanning revealed that the deterioration zone was deformed along large fracture zones and layers. Unlike limestone slopes, the intact sandstone underground might be degraded by changes in water. There are few inclinometers and no deformation or weak deformation, which requires long-term monitoring. The relevant research methods provide an important reference for determining the instability and failure trend of the reservoir bank slopes.