Soil is a major reservoir for contaminants as it posseses an ability to bind various chemicals. These chemicals can exist in various forms in soil and different forces keep them bound to soil particles. It is essential to study these interactions because the toxicity of chemicals may strongly depend on the form in which they exist in the environment. Another thing is that soil variability and some environmental properties (e.g. climate factors) may change equilibrium found in soil and cause leaching of trace toxic elements like heavy metals tightly bound to soil particles.

Mathematical and computer modeling help us with understanding processes occurring in soils. A number of models are being developed now which can quantitatively predict movements and sorption of heavy metals in soil with good accuracy. However, investigations for determining chemical properties of soil, heavy metal interactions, should continue because a lot of questions about this strongly heterogenic matrix is still nor answered.