Libang Ma

Mining and smelting constitute primary anthropogenic sources of persistent heavy metal (HM) contamination in soils, posing severe ecological and health threats globally. Conventional risk assessment often fails to discriminate between natural weathering inputs and anthropogenic emissions while struggling to prioritize pollution sources by risk severity, hindering targeted remediation. This study overcomes these limitations by integrating positive matrix factorization (PMF) source apportionment with ecological risk assessment (ERA) and health risk assessment (HRA) frameworks to quantify source-specific risks. Applied to soils surrounding an abandoned antimony smelter in Gansu Province, HM concentrations (excluding Cr and Ni) exceeded background levels, with Sb reaching 935.28 mg/kg. Extreme pollution by Sb and Cd was observed, while 95% of samples showed moderate to heavy contamination levels. PMF identified four primary pollution sources: industrial activities (27.82%), mining (30.43%), natural sources (21.11%), and transportation (20.64%). ERA indicated extreme ecological risks attributable primarily to Sb, Cd, and Hg, with substantial contributions from industrial (50.11%) and mining (31.83%) origins. HRA revealed unacceptable non-carcinogenic (24.90 for children, 4.06 for adults) and carcinogenic risks (1.83 × 10⁻⁴ for children, 1.11 × 10⁻⁴ for adults). Ingestion served as the predominant exposure pathway, primarily from Sb and As for non-carcinogenic risks and carcinogenic risks, respectively. Integrated risk apportionment demonstrated dominant non-carcinogenic risk contributions from mining (53.33%) and industrial (43.62%) activities primarily via Sb, while industrial (36.60%) and natural (35.81%) sources were major carcinogenic risk contributors with Ni and Cd as the key contaminant. This quantitative source-risk linkage provides a science-based foundation for prioritising control measures and enabling safe reclamation of polluted industrial sites.

The exploration of homestead withdrawal can provide an important decision-making reference and theoretical support for deepening the reform of rural land system and accelerating the process of urban-rural integration and development. This paper takes Qingshui county in Gansu province as the research area, and based on the perceived value theory, combined with the hierarchical regression model, analyses the mechanism of risk perception and comprehensive satisfaction on the willingness of farmers to withdraw from homesteads by using 1025 micro-survey data, and further classifies the types of willingness of farmers to withdraw from homesteads. The results show that: (1) Risk perception negatively affects homestead withdrawal, with cognitive risk perception having the strongest effect and the facility risk perception being the weakest. (2) Comprehensive satisfaction has a negative effect on homestead withdrawal, with life satisfaction having the most significant effect and the satisfaction with public services and facilities being the weakest. (3) In the analysis of the contribution of independent variables, in terms of risk perception, the risk perception of the homestead withdrawal is the highest, and the perception of owning multiple homesteads is the lowest. In terms of comprehensive satisfaction, the water and electricity facilities receive the highest ratings, while cultural and entertainment amenities are rated the lowest. (4) Based on the two-dimensional analysis framework of 'psychological perception-emotional cognition', the willingness of farmers to withdraw from homesteads can be classified into four types: high-risk avoidance, high-satisfaction trade-off, medium-risk guidance, and low-risk drive. This paper proposes categorized governance strategies to address the characteristics of different types of farm households, aiming to provide a decision-making basis for sustainable rural land use.

Drought is a common hydrometeorological phenomenon and a pervasive global hazard. To monitor global drought-wetness conditions comprehensively and promptly, this research proposed a spatial distance drought index (SDDI) which was constructed by four drought variables based on multisource remote sensing (RS) data, including the normalized difference vegetation index (NDVI), land surface temperature (LST), soil moisture (SM), and precipitation (P), using the spatial distance model (SDM). The results showed that the consistent area of SDDI with the 1-month and 3-month standardized precipitation-evapotranspiration index (SPEI1 and SPEI3), and the self-calibrating Palmer drought severity index (scPSDI) accounted for 85.5%, 87.3%, and 85.1% of the global land surface area, respectively, indicating that the index can be used to monitor global drought-wetness conditions. Over the past two decades (2001–2020), a discernible spatial distribution pattern has emerged in global drought-wetness conditions. This pattern was characterized by the extreme drought mainly distributed deep within the continent, surrounded by expanding moderate drought, mild drought, and no drought areas. On the annual scale, the global drought-wetness conditions exhibited an upward trend, while on the seasonal and monthly scales, it fluctuated steadily within a certain cycle. Through this research, we found that the sensitive areas of drought-wetness conditions were mainly found on the east coast of Australia, the Indus Basin of the Indian Peninsula, the Victoria and Katanga Plateau areas of Africa, the Mississippi River Basin of North America, the eastern part of the Brazilian Plateau and the Pampas Plateau of South America.

Natural ecosystems are changing more quickly because of human activities, the type and intensity of which are directly correlated with vegetation greenness. To effectively determine how human activities affect trends in vegetation under climate change, we must differentiate between various types of human activities. The GTWR model can study the spatiotemporal non-stationary relationship between the NDVI trend and climate change. The GTWR model was incorporated into multiple climate variables and improved residual analysis to quantify the contributions of climate change and human activities on vegetation change trends in the Hexi region during different periods. This study divides human activities into four groups based on land use change: urbanization, agricultural expansion, desertification, and ecological restoration to further investigate their contribution to vegetation greenness change. The results showed that in 56.9% of the significant vegetation greening trends between 1982 and 2015, climate factors contributed only 7.4%, while human factors contributed a significant 22.7%. Since the ecological restoration project implemented in 2000, the expansion intensity of ecological restoration and urbanization increased significantly, followed by agricultural expansion and desertification. For the considerable greening trends in the Hexi region, the ecological restoration project contributed 26.7%, while agricultural expansion and urbanization contributed 17.5% and 4.6%, respectively. This study aims to provide new insights for more accurate simulation and evaluation of the interaction effects of climate change and human socio-economic development on vegetation growth.

Basic education pursues “balance” and “quality” under the premise of “universalization”. High-quality and balanced education is the general strategy of international education. We used urban network tools to measure the spatial equity of three types of basic educational facilities (kindergarten, primary school, and middle school) in the main urban area of Lanzhou City, China, from the perspective of supply and demand. This can optimize the allocation of educational facilities, and make up for the shortage of basic educational facilities. It can also provide a scientific reference and new ideas for research on public service facilities. The conclusions are: (1) The distribution of basic educational facilities presented a typical pattern of belt-shaped clusters, river trends, and dense east and sparse west. The spatial dislocation between facilities and residential buildings was significant and occurred in numerous instances. (2) The supply of basic educational facilities was weak. There were significant differences in spatial accessibility among different types and regions. The spatial accessibility of kindergartens (34.83%) was the best with regard to walking conditions, followed by primary schools (27.43%) and middle schools (21.11%). (3) The distribution of basic educational facilities was affected by factors such as historical development, natural geography, social economies, and the travel behaviors of residents; (4) It is necessary to improve the problem of spatial imbalance through the implementation of refined planning management and resource allocation of infrastructure, the construction of a “community life circle”, and the establishment of an early warning mechanism for academic degree attainment combined with big data.

The land problem is the key to the implementation of the rural revitalization strategy, and the land suitability evaluation is the basis for the renovation and classification of idle rural residential areas. Taking Yuzhong County in the Loess Hilly region of Longzhong, China as the research area, this study constructed an idle residential identification matrix by combining the evaluation results of ecological protection suitability, agricultural production suitability, and construction and development suitability, and realizing renovation zoning of rural residents through the advantage type identification method. The results show that: (1) The waste in rural residential is serious, and there are significant phenomena of “one household with two houses” and “one household with multiple houses.” The renovation potential of 1700 idle rural residential patches is 1.18 km². (2) The spatial differences in the suitability of rural residents in Yuzhong County are significant, and through the rational guidance and planning layout of rural residential renovation, it can provide an important decision-making basis for the rational utilization of rural residents and national land–space planning. (3) The renovation of rural residential should be guided by national land–space planning; make a solid plan for the renovation of rural residential areas; formulate a scientific plan for the renovation, relocation, and reuse of rural “hollow houses”; stimulate the vitality of rural land resources; and promote the revitalization of the countryside and the improvement of the rural living environment.

In order to break away from the overreliance on a single industry and the simple supply of agricultural products, rural multifunctional research has gradually received public attention. To a certain extent, multifunctional classification governance paths can enhance rural competitiveness and land use efficiency and alleviate the problems of local poverty and unbalanced development in rural regions. Based on the theory of rural multifunctionality, this paper reveals the spatial characteristics and coordination of rural multifunctionality at the township scale, analyzes the barrier functions of different regions, and clarifies the direction of rural development using the rural assessment method, the trade-off synergy model, and the dysfunctional diagnostic model, taking Yongchang County in the western corridor of China as an example. On this basis, we further discuss the path selection of rural governance in northwest China. The results show that: (1) The spatial distribution of rural functions has pronounced heterogeneity, with better life security functions and ecological background functions, and similar spatial patterns; economic development functions are on the low side, showing the divergent characteristics of enhancement from the township center to the surrounding area. The functions of agricultural production are low, and the spatial distribution is similar to that for the living guarantee function. (2) The living guarantee function has a strong trade-off effect on the ecological background function, and the living guarantee and ecological background functions have a synergistic effect on the agricultural development function. (3) We classified types of villages according to the intensity index of village function trade-offs and clarified the functional development characteristics of each administrative village. The incompatibility of village functions caused by different demands is the root hinderance to the development of villages.

The evaluation of rural livability for different groups of left-behind people and proposing classified governance paths are of great practical significance to solve the problem of sustainable development of left-behind villages. Taking Jinchang, China as an example, this paper aims to construct a rural livability evaluation index system based on identifying the types of left-behind villages, which combines the “individuality + commonality” of different left-behind subjects, analyzes the livability level of left-behind villages and proposes a classified governance path to help solve the problem of sustainable development of left-behind villages. The results show the following: (1) The types of left-behind villages are mainly left-behind children and left-behind elderly types, accounting for 68.75% of the total number of left-behind villages. (2) There are large differences in the livability of individual characteristics of the villages. The average livability for children is the largest, reaching 0.6608. The average livability for women is the smallest, being only 0.1418. The livability values for the elderly and children are mainly in the medium-value areas, while the livability for women is mainly in the low-value areas. (3) The overall livability level of the villages is low, mainly falling in the low-value areas. The evaluation units with values higher than the average accounted for 40.625% of the total. The level of meeting the demands of the left-behind population in villages is low. The overall levels of economic development, public services, infrastructure, and configuration need to be optimized and improved, and the living and production conditions need to be further improved. (4) According to “left-behind + livable”, we classified the villages into five types: optimizing and upgrading villages, improving short-board villages, balanced developing villages, upgrading potential villages, and comprehensive upgrading villages. In the future, it is necessary to carry out classified governance from various aspects, such as improving governance, making up for shortcomings, coordinating and balancing, and comprehensively improving quality to achieve the ultimate goal of sustainable rural development.