Simulation Study on Risk and Influencing Factors of Cadmium Loss in Contaminated Soil

Abstract

Cadmium (Cd) in contaminated soil not only enters surface water via rainfall runoff but also penetrates groundwater, adversely affecting human health through the food chain. This research examined three kinds of soil from Luoping County in southwestern China, with different Cd pollution levels. Simulated rainfall and soil column leaching experiments were conducted to explore the risks and factors influencing Cd loss in surface runoff and underground leaching water at different ground slopes (6°, 12°, 18°, and 24°), rainfall intensities (30, 60, and 90 mm∙h−1), and soil profile conditions. The results show that the risk of soil Cd runoff loss increased at a higher rainfall intensity or Cd pollution degree, reaching a peak at a ground slope of 18°. The main factor affecting soil Cd runoff loss was rainfall intensity followed by Cd soil pollution degree and slope. The risk of soil Cd leaching loss was mainly determined by the leaching time and soil depth. The primary factor affecting soil Cd leaching loss was leaching time, followed by soil depth. The soil organic matter (SOM) concentration and pH minimally affected soil Cd loss. The research results provide a theoretical basis for risk management and control of cadmium loss in contaminated soil, and indicate that the environment-friendly water treatment method of high concentration Cd polluted runoff deserves attention.