Distribution characteristics and investigation evaluation of ammonia nitrogen in the soil and groundwater of a chemical plant

In this study, we analyzed the distribution characteristics of ammonia nitrogen, and evaluated the pollution status of the soil and groundwater in this legacy site. The results revealed that the concentration of ammonia nitrogen in the soil ranged from 2.36 to 32.7 mg/kg, and the areas with higher ammonia nitrogen concentration were the compression workshop, conversion workshop, sewage treatment area, and slag yard, the concentration of ammonia nitrogen in these areas ranged from 10.1 to 32.7 mg/kg. The groundwater ammonia nitrogen concentration ranged from 0.04 to 1.47 mg/L, the average value was 0.526 mg/L. Soil and groundwater ammonia nitrogen pollution in the plant area was mainly attributed to the node leakage of waste water pipes, and the investigation and evaluation results revealed that the soil test results of this site are consistent with the corresponding screening values. As the groundwater in this site is not used for drinking and other purposes, its risk to human health is considered acceptable. The detection indicators of groundwater in some plots exceed the Class III or IV standards, so long-term monitoring and retrospective risk assessment are the focus of future risk management and control of the plots.