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China has entered the stage of rapid urbanization since the 1990s, resulting in a series of environmental problems. Based on the nighttime light remote sensing data and land use data from 1995 to 2020, we extracted the compound night light index (CNLI) to measure the urbanization level of mid-southern Liaoning urban agglomeration, evaluated habitat quality by InVEST model. We examined the relationship between urbanization level and habitat quality in mid-southern Liaoning urban agglomeration by using the correlation analysis method and the geographic weighted regression model. The results showed that CNLI increased by 0.14 from 1995 to 2020. The urbanization level increased continuously, with a pattern of "low in the east and high in the west". The habitat quality decreased by 0.005, showing a pattern of "high in the east and low in the west". The ecological environment became worse. There was a significant negative spatial correlation between urbanization level and habitat quality in mid-southern Liaoning urban agglomeration. The negative impact of urbanization level on habitat quality gradually decreased. In order to alleviate habitat degradation caused by urbanization and realize the coordinated and sustainable development of regional social economy, it was urgent to take a series of measures, such as delimiting the ecological protection red line, improving the intensive use of land, delimiting the urban boundary, promoting the coordinated development of regional integration.

The vegetable greenhouse soils in Yanglou Town, Ruzhou City, Henan Province were taken as the research object in the present study to explore the difference in soil physical and chemical properties and the total and fraction of heavy metals of different planting years. The potential ecological risks of heavy metals in greenhouse soils with different planting years were assessed by using single and comprehensive potential ecological risk index methods. The results showed that the soil pH of vegetable greenhouses increased, and fertility factors such as organic matter, available phosphorus, and alkali-hydrolyzable nitrogen accumulated to a certain extent compared to the control group, whereas catalase showed a decreasing trend. Correlation analysis showed that the planting years were significant positively correlated with pH ( P <0.05) and organic matter ( P <0.01) and significant negatively correlated with catalase ( P <0.01). The amount of heavy metals in the vegetable greenhouse soils increased with the increase in planting years, among which Cu, Zn, and Cd increased most obviously, with maximum increases of 129.14%, 204.17%, and 161.11%, respectively. The proportion of acid-soluble and reducible heavy metals in the vegetable greenhouse soils also increased gradually with the planting years, and the proportion of residual heavy metals decreased correspondingly, which resulted in the heavy metals transforming into fractions easily absorbed by plants. The results of the single potential ecological risk index showed that Cd in vegetable greenhouse soils had a strong ecological risk with the increase in planting years, whereas Cu, Pb, Zn, and Ni were in the mild risk category. The comprehensive potential ecological risk index showed that the heavy metals in the vegetable greenhouse soils of different planting years have reached a strong or very strong ecological risk.

Surface farmland soil samples were collected from 135 different sites in a 64 km 2 area around a lead and zinc smelter in Jiaozuo City, China. The concentration of the selected heavy metals (Cu, Zn, Pb, Cr, Cd, Ni, V, and Co) was analyzed and the spatial distribution of these heavy metals in the farmland was determined using the kriging interpolation technique (ArcGis 10.1). The enrichment factor, potential ecological risk model, and potential health risk model were used to assess the contamination level and potential risk of heavy metals in farmland surface soil. The results show that the average contents of Cd, Pb, Cr, and Zn in farmland soil are higher than the background content of these metals in the Henan Province and the average content of Cd is 2.8 times higher than that of class Ⅱ of the environmental quality standard for soils in China (GB 15618-1995). The heavy metal contamination in the west of the study area is higher than that in the east and the soil around the lead and zinc smelter (within 3 km) is severely contaminated with Pb and Cd, which is consistent with the location of the industries causing the pollution. The enrichment factors show that the soil is severely contaminated with Cd; partial sampling points are seriously contaminated with Pb, Cu, and Zn; the Cr and Co pollution is small; and Ni and V are almost not affected by human activities. The results of the risk assessment indicate that Cd poses serious ecological and health risks, Pb and Cu pose serious ecological risks, and Cr poses a serious cancer risk.