In this paper, using the leaching models, we quantified the leaching content of Cd, Pb, Cu, and Zn, and estimated the ecological risk changes in farmland soil caused by leaching and the ecological risk in leachate in China. Jiangxi, Guangxi, Guizhou, Hainan, Hunan, Zhejiang, Guangdong, and Chongqing are hotspot areas. The leaching of Cd in these regions exceed reported mean values in Europe (2.56 g ha⁻¹ year⁻¹). Although the total ecological risk of heavy metals in the soil of various provinces (ranged from 20 to 130) was generally low, Cd was the most important contributor to ecological risks, while 9 provinces exhibited considerable ecological risk from Cd. The calculated Cd, Pb, and Zn in leachate exceed drinking water standards (GB 5749-2022) in five provinces. Overall, the leaching of heavy metals in Chinese agricultural soils, particularly in the southern regions, is a critical issue that warrants attention. Soil pH is the most prominent factor influencing heavy metal leaching. A 5% increase in pH reduces leaching by 31.2% for Cd, 25.42% for Pb, 22.07% for Cu, and 38.37% for Zn. Adjusting the pH to 6 can effectively solve the problem of excessive heavy metal content in leachate in most areas. The study recommends prioritizing groundwater monitoring in critical provinces such as Jiangxi and adjusting the soil pH of farmland in key regions.

The accurate prediction of the water-permeable fractured zone (WFZ) height is critical for preventing water inrush disasters in longwall mining, especially in ecologically fragile areas. Current methods for evaluating the WFZ often neglect the strain-softening behavior of rock, leading to a commonly observed deviation in predictions. This study investigates the overburden failure mechanisms and WFZ development by integrating in-situ monitoring, empirical analysis, and numerical modeling using the Mohr-Coulomb (MC) model and an advanced Strain - Softening (SS) model. The SS model accurately replicated the progressive failure of the overburden, predicting a WFZ height of 144.5 m, which closely aligned with the in-situ data. In contrast, the MC model, with its assumption of constant post-peak strength, underestimated the height by 16 m, yielding a result of 128.5 m. This discrepancy concludes that the strain-softening behavior of rock is a dominant factor controlling WFZ development. Relying solely on traditional empirical formulas or simplistic constitutive models may lead to non-conservative underestimations of the WFZ, thereby escalating mining safety and ecological risks. The validated SS model provides a superior tool for realistic water hazard assessment and strategic mine planning.