No abstract

No abstract

Along with the accelerated shift of coal mining to the ecologically fragile west, the contradiction between coal resource development and ecological protection in the western arid and semiarid coal mining areas is rapidly intensifying. Based on the above background, this thesis takes the coal mining area in the arid and semiarid regions as an example; applies the theories of ecology, coal mining subsidence, geodesy, and ecological restoration; uses remote sensing in synthetic aperture radar (SAR), geographic information system (GIS), and mathematical modelling to reveal the ecological evolution law of the mining area; measures the ecological damage of the mining area; and then proposes a reasonable ecological restoration strategy. The surface deformation monitoring study in the study area shows that on the whole, some areas in the study area have different degrees of surface subsidence disasters, and the maximum surface subsidence value exceeds 800 mm. From the distribution of surface subsidence in the study area, surface subsidence disasters mainly occur in the eastern and central mountainous areas rich in coal resources, as well as in the mining areas west of the Yellow River, and the subsidence basins are distributed in a series of irregular concentric ovals. In terms of the scale of surface subsidence in the study area, a total of 230.03 km2 of land in the study area showed surface subsidence hazards during the monitoring period, accounting for 13.78% of the total area of the study area, of which the area of severe subsidence was 44.98 km2 (2.69%). The area of more serious subsidence area is 101.33 km2 (6.07%), and the area affected by subsidence is 83.72 km2 (5.01%).

PAHs were widely detected accumulated in saline and hypersaline environments. The halotolerant and halophilic microbes were considered as the most suitable player for the elimination of PAHs in such environments. In this study, consortium 5H was enriched under 5% salinity that was able to completely degrade phenanthrene in 5 days. By high-throughput sequencing, consortium 5H was identified mainly composed of Methylophaga, Marinobacter and Thalassospira. Combined with the investigation of intermediates and enzymatic activities, the degradation pathway of consortium 5H on phenanthrene was proposed. Meanwhile, consortium 5H was identified with ability to tolerate a wide range of salinity (1% to 10%) and initial PAHs concentration (50 mg/L to 400 mg/L). It was also able to work under neutral to week alkaline conditions (pH from 6 to 9) and the phytotoxicity of the produced intermediates showed no significant difference with distilled water. This study expanded the knowledge of PAH-degradation under hypersaline environments and consortium 5H was proposed with a good potential for the elimination of PAHs pollution under saline/hypersaline environments.

No abstract