To this point we have discussed the importance of two of Earth’s most important, critical compounds necessary to sustain life on Earth: the environmental mediums of air and water. Moreover, we have also discussed the basic economic principles involved in maintaining and ensuring the quality of air and water, but at this point our discussion is incomplete. Beyond air and water being necessary to sustain life, having safe air to breathe and safe water to drink can simply be refreshing and

revitalizing. But clear air and clean water alone do not complete the picture for us; we also need two more mediums: land and life. We will discuss life and biodiversity later; for now, we are interested in terra firma-that is, the solid earth, dry land, and solid ground on which we inhale our clean air and drink our safe water. In this chapter, we talk about the basics of soil, land cleanup, and land reuse. More specifically, we present a discussion covering the benefits, costs (economics), and impacts of land cleanup and reuse.