A simulation program on change trend of pollutant concentration under water pollution accidents and its application in Heshangshan drinking water source area

With the rapid development of the economy in recent years, water pollution accidents have occurred frequently, and accidents that have occurred in drinking water source areas in particular have seriously affected public health and social safety. The objective of this study is to develop a program to predict the diffusion and migration processes of pollutants after water pollution accidents and apply it to the Heshangshan drinking water source area. Taking Cd as a typical pollutant, the results indicated that Cd concentrations at the water intake reached a maximum value of 1.2490 × 104 mg/L at 14.08 min after a hypothetical accident, and the time when the area lost the function of drinking water supply was from 8.35 min to 24.23 min after the accident. Regarding the drinking water source area, the Cd concentration exceeded the related standard during the period from 7.29 min to 41.47 min after the accident, which indicated that it was polluted seriously by the accident for that duration. Moreover, the pollutant entered into the study area at 7.00 min after the accident and had passed through at 45.63 min after the accident, which demonstrated that emergency measures should be taken for this duration. The developed simulation program could simulate the spatial distribution and temporal change of pollution, calculate maximum concentration of pollutants, present pollution scope and time, and forecast diffusion and transport processes. This study will give relative researchers and managers a reference and tool for pollutant migration and water resources management after water pollution accidents.