Abstract:In order to study the migration and formation mechanism and pollution causes of pollutants in surface water and ground water in Longnan rare earth mining area, the present situation of surface water and ground water quality around the mining area was monitored. The pH value and concentrations of sulfate, nitrate, nitrite and ammonia nitrogen in surface water and ground water around the study area were analyzed and determined. The improved Nemero composite pollution index method and health risk assessment model were used to assess the pollution degree and health risk of different age groups. The results show that the highest Composite Pollution Index (CPI) of 54.19 is found at the surface water pit, which is a serious pollution level. The lowest CPI of 2.119 is found at the Hangang Bridge in Guanxi, which is a cleaner level. The integrated pollution index of the downstream of the treatment station in the material pit, Huangsha River and Lintang has reached the serious pollution level. The integrated pollution index of the ground water sampling points have reached the standard, and the water quality is clean. The results of the health risk evaluation show that nitrate in surface water and ground water in the study area poses a greater health risk to human beings, followed by nitrite and ammonia nitrogen. After the calculation of the non-carcinogenic health risk, the impact of drinking ground water and surface water on people of different age groups is that young children > young people > adults, so more attention should be paid to the safety of the water used by young children aged 0—6 years old in the vicinity of the Longnan rare earth mining area.