The relationship between urbanization and soil health is currently a global concern. Therefore, it is necessary to quantify an urbanization indicator in the context of soil environmental pressures. Our study analyzed five core cities in the central Yunnan urban agglomeration to investigate the relationship between urbanization and soil heavy metal concentrations. The results show that soil heavy metal concentration in old urban blocks were higher than that in the new urban blocks with different urbanization contexts. We constructed a new Urbanization Environmental Pressure Index using a genetic algorithm. Segmented regression analysis indicated that there were often thresholds in the relationships between urbanization and heavy metal pollution; when urbanization exceeds the thresholds (between -0.502 and 0.260), soil heavy metal pollution significantly increased. The study also employed spatial correlation analysis to identify areas of heavy metal pollution caused by urbanization, which are mainly concentrated in old urban blocks. This research provides a new perspective for understanding the impact of urbanization on soil heavy metal pollution and offers a scientific basis for the prevention and control of urban soil heavy metal pollution.
Liu et al. (Fri,) studied this question.