The behavior and interaction of pollutants with soil comprise of various physical,
chemical, and biological processes that take place in all three components (solid, gas and
liquid) of the soil medium. They generally include three main groups of processes:
1. Retention
2. Infiltration, diffusion and transport by soil solutions
3. Alteration, transformation, and initiation of chemical changes within the soil
While the first two groups include mainly physical processes, by which pollutants are
transported and distributed in the soil, the third group comprise of only chemical and
biological processes, by which pollutants are transformed or stored as residues in the
interstitial space.