Evaluation of eco-environmental quality for the coal-mining region using multi-source data

Evaluation and dynamic monitoring of ecological environment quality in mining area based on improved CRSEI index model

Large-scale open-pit mining in mining areas will cause serious damage to the ecological environment. Building a "green mine" is an essential part of implementing sustainable development. In order to explore the changing characteristics of the environmental quality of the open-pit mining area and provide a scientific basis for improving the ecological environment of the mining area. Taking Sijiying open-pit mining area as the research area, based on four Landsat images from 2000 to 2022, the four index components of greenness, humidity, dryness and heat were integrated, and an improved remote sensing ecological index CRSEI was constructed by principal component analysis to dynamically evaluate and monitor the ecological environment quality of the mining area. The results show that the average correlation between CRSEI and the index components is higher than the average correlation between the components, indicating that it has a favorable expression effect on the ecological quality of the mining area. The ecological environmental quality of the study area experienced a shift to the poor grade, and the poor ecological quality area was mainly distributed in industrial and mining land and construction land, with the mean CRSEI of 0.668, 0.474, 0.460 and 0.494, respectively. The results of dynamic monitoring showed that the proportion of ecological improvement area (41.43 %) was greater than that of ecological deterioration area (33.29 %) in the study area in the past 22 years, and additional restoration efforts should be made to achieve sustainable development of the ecological environment.

Nano-scale analysis of uranium release behavior from river sediment in the Ili basin

Due to the limitations of the conventional water sample pretreatment methods, some of the colloidal uranium (U) has long been misidentified as "dissolved" phase. In this work, the U species in river water in the Ili Basin was classified into submicron-colloidal (0.1-1 μm), nano-colloidal (0.1 μm-3 kDa) and dissolved phases (< 3 kDa) by using high-speed centrifugation and ultrafiltration. The U concentration in the river water was 5.39-8.75 μg/L, which was dominated by nano-colloidal phase (55-70%). The nano-colloidal particles were mainly composed of particulate organic matter (POM) and had a very high adsorption capacity for U (accounting for 70 ± 23% of colloidal U). Sediment disturbance, low temperature, and high inorganic carbon greatly improved the release of nano-colloidal U, but high levels of Ca²⁺ inhibited it. The simulated river experiments indicated that the flow regime determined the release of nano-colloidal U, and large amounts of nano-colloidal U might be released during spring floods in the Ili basin. Moreover, global warming increases river flow and inorganic carbon content, which may greatly promote the release and migration of nano-colloidal U.

Land Use Transformation Based on Production−Living−Ecological Space and Associated Eco-Environment Effects: A Case Study in the Yangtze River Delta Urban Agglomeration

We investigate the eco-environmental effects and the driving factors of transforming the production–living–ecological space (PLES) land use function and offer a scientific foundation for developing regional territorial area and environmental preservation. Eco-environment quality index and ecological contribution ratio are used to analyze the spatial–temporal evolution characteristics and eco-environment effects of land use transformation in the Yangtze River Delta Urban Agglomeration (YRDUA) over the three time periods of 2000, 2010, and 2020, and the geographic detectors are used to analyze the factors that influence the spatial difference of eco-environment quality (EEQ). The findings indicate the following: (1) The land use transformation of YRDUA is primarily shown in the shrinkage of the production land area, the stability of ecological land, and the rapid increase of living land. The area of ecological land, such as water, forest, and pasture, has remained relatively steady from the perspective of secondary land types. In contrast, the area of urban and rural living land has significantly increased. (2) Most land use environment comprises the lower-value zone, accounting for about 50%. The area of the low-value zone has continued to rise owing to the rapid urban and rural living land development, tending to continuous growth. (3) Both the ecological improvement and degradation trends are present simultaneously, although the ecological improvement trend is less prominent than the environmental degradation trend. The primary factor is improving the eco-environment by transforming agricultural production land into forest, water, and ecological pasture land. The degradation of the regional EEQ is mostly due to the occupation of agricultural production land by urban and rural living land. (4) Considering natural elements such as altitude, precipitation, and slope, the extent of land use impacts the EEQ. The combination of several factors has changed the EEQ of the YRDUA. The effect of any two elements is stronger than that of a single factor.

Study on Ecological Loss in Coal Mining Area Based on Net Primary Productivity of Vegetation

Opencast mining contributes to the severe disturbance of vegetation and serious damage to the ecological environment. Scientific assessment of the ecological losses may provide guidance for the sustainable land use in mining areas. This study uses the Carnegie Ames Stanford Approach (CASA) model to estimate the net primary productivity (NPP) of vegetation in the Pingshuo mining area from 2006 to 2020 and uses statistical analysis and mathematical models to study the impact of mining and land reclamation on NPP. The results show that NPP decreased slowly at a rate of 0.809 gC/(m2·month) per year. In 2006, the urban area of Pinglu and the opencast coal mining area were located in the western part of the study area, while the eastern part was distributed with a large amount of grassland, forested and cultivated land, and the NPP showed a high pattern in the east and low in the west. With the continued eastward movement of Antaibao and Anjialing mining areas, as well as the construction and continuous westward expansion of the East opencast mine, the pits of all three opencast mines moved to a central location in 2020, changing the spatial distribution of NPP to high in the surroundings and low in the middle. The NPP within the three opencast mines decreased significantly, but the change in NPP increased from −7.34 gC/(m2·month) to 7.15 gC/(m2·month) as the reclamation area increased, indicating that mining increased ecological losses while land reclamation mitigated them. The variation of NPP within 600 m outside the mining area is 2.06~7.45 gC/(m2·month), and 0.11~1.00 gC/(m2·month) from 600 m to 1000 m, indicating that NPP is sensitive to the influence of mining. The results may provide guidance for further analysis of the impact of mining on local environments and exploration of more appropriate land reclamation measures.