Acid mine drainage (AMD) is a major anthropogenic source of heavy metal discharge worldwide. However, little research has been carried out on the development of AMD in abandoned pyrite mines and the heavy metal contamination of mine surface water. The aim of this study was to investigate and assess heavy metal pollution in three streams within an abandoned pyrite mine area in southeastern Shaanxi Province, China. Surface water pollution was assessed using the pollution index assessment method and the health risk assessment model. The results showed that the combined heavy metal pollution indices of the surveyed rivers were Tielu Creek (4699.227), Jiancao Creek (228.840), and Daoban Creek (68.106). After multivariate statistical analysis, it was found that the tailings slag and mine chamber in the abandoned mine area were the main causes of AMD, and AMD posed a serious risk of heavy metal pollution to the surrounding waters. The risk of carcinogenicity of heavy metals is also quite high in the surface water of mining area. Therefore, there is an urgent need to ecologically manage heavy metal pollution from abandoned mine sites, and this study provides insights into understanding heavy metal pollution in the aquatic environment of abandoned mine sites.

Heavy metal pollution of groundwater will not only destroy the ecological environment but also negatively affect the functioning of the human liver. Tracing the source of groundwater pollution is an important way to protect groundwater resources. FloPy is promoting the use of big data in the groundwater field, especially in groundwater resource planning and management and contaminant traceability. This paper takes Mn as an example and codes a simulation-optimization model for solving the groundwater pollutant traceability problem using FloPy. The Bayesian optimization and strengthen elitist genetic algorithm (SEGA) algorithms are then used to optimize the hydraulic conductivity and pollutant sources in the study area. The results show that the model runs in 411 s, which is an acceptable amount of time spent, the slope of the fitted curve between the model-calculated water level and the actual observed water level is 0.914, and the contaminant traceability results can successfully locate the contaminant sources in real engineering problems. The numerical groundwater flow model and solute transport model can be quickly built, modified, and run by writing code, and can be easily and efficiently coupled with various optimization algorithms with FloPy.

The exploitation and utilization of shallow geothermal energy are of great significance to realizing China’s “double carbon” goal and promoting a green economy and social development. However, many projects using ground source heat pumps to exploit shallow geothermal energy have disrupted the thermal balance of the geothermal field due to insufficient preliminary research, affecting the sustainable utilization of shallow geothermal energy. Therefore, a 3D groundwater–thermal coupling model was established in this paper using the geotemperature data of a ground source heat pump system in Xi’an. This study investigated the response characteristics of the groundwater–thermal system to the ground source heat pump system using the numerical simulation method and discussed the optimal layout scheme of the system on this basis. After years of simulation, it was found that long-term operation of the ground source heat pump system under actual operation produces “cold accumulation”. In addition to artificial intervention of the groundwater flow field, the effects of the system operating parameters and layout settings are also investigated to alleviate this cold accumulation. The results show that changing the operating parameters so that the heat transfer is the same in winter and summer, cross-locating the cooling holes with the heating holes, and placing multiple pumping and recharge wells downstream can alleviate the cold accumulation in the heat exchange zone. The results of this numerical simulation study provide an important reference for solutions to mitigate the accumulation of ground cold and heat in developing shallow geothermal energy using borehole heat exchangers and to suppress the downstream geotemperature disturbance via the ground source heat pump system.