Abstract. Figuring out the regional ecological environment quality and ecological change is critical for ecological environment monitoring and management and urban construction planning. Based on the remote sensing ecological index (RESI), we evaluate the ecological quality and ecological change from 1999 to 2019 of Anqing city. Multi-temporal Landsat images are used to extract the four indicators of humidity, vegetation, heat and dryness, respectively. Then the RSEI is calculated by principal component analysis. The results show that the ecological quality of Anqing city declined from 1999 to 2019 and then grew slowly from 2009 to 2019. The eco-environmental quality of Anqing city dropped slightly from 1999 to 2019, and the regions with worse quality grades exceeded those becoming better. Particularly, we find that from 1999 to 2009, the area where the ecological quality became better made up 18.31% of the urban area, while the worse ecological area accounted for 29.68% of the urban area; from 2009 to 2019, the area of improved ecological environment reached 24.35%, while the area of degraded quality constituted 41.36%. Land-use changes dominated eco-environmental quality. The areas of poor eco-environmental quality expanded in residential regions and eco-environmental quality of mountainous area improved since returning cultivated land in steep hills into forest. The RSEI results are expected to provide a quantitative foundation for planning sustainable development and the rational use of resources in Anqing city.

The authors discuss the genesis of the regional gravity and magnetic anomalies in the northern part of Eastern Xinjiang, a correlation analysis was carried out between the regional gravity anomaly and the regional magnetic anomaly. Through data processing and integrated interpretation of the gravity and magnetic data in the study area, the Bouguer gravity anomaly and the magnetic anomaly by reduction to the pole were separated. Then, the regional gravity and magnetic anomalies across multiple scales were extracted; in addition, the correlation coefficients between the regional gravity anomaly and the regional magnetic anomaly at different scales were calculated. Finally, the features of the gravity and magnetic fields, their geological significance, and the origins of these regional gravity and magnetic anomalies were analyzed. The results showed that the regional negative gravity anomaly in the Turpan-Hami basin and the Santanghu basin was mainly caused by Cenozoic and Mesozoic strata; the regional positive magnetic anomaly was mainly caused by the Precambrian metamorphic basement. The study revealed that the regional positive gravity and magnetic anomalies resulted from the crust and the mantle substances in the eastern part of the Junggar basin. While the regional positive gravity anomaly was mainly caused by Pre-Mesozoic strata, and the regional negative magnetic anomaly by the sedimentary formation and intermediate acid rocks in the Bogeda-Harlike folded zone and the Jueluotage anticlinorium. The regional negative gravity and magnetic anomalies in the active zone of the northern margin of Tarim were mainly caused by the sedimentary formation and intermediate acid rocks.

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The groundwater and soil of Nanjing 1211 Chemical Plant were investigated by the method of high-density resistivity after the plant closure. The results show that there are high resistance anomaly areas of aquifer and soil between 17 and 45 meters where the resistivity is higher than 100 ohm-m. Chemical analyses show that the high resistance anomaly areas are caused by DNAPLs pollution. The spatial distribution of underground pollutants was delineated and the origin of the contaminants was confirmed. The research shows that high-density resistivity method is effective in locating heavy organic pollution of groundwater and soil of chemical plants. The method is both economical and convenient to detect organic pollution and is recommended for such usage.