This section presents information on remediation technologies and corrective measure techniques that can be implemented to contain and clean up environmental contamination. Before selecting an environmental technology a site owner should answer several basic questions:

• What medium has the contamination affected? (Air, soil, groundwater, surface water).

• What is causing the contamination?

• Is the contamination level high enough to warrant remedial action?

Cleanup requirements are based on federal or state environmental laws, which define "contamination" and sometimes establish graduating levels of contamination. Such guidelines are often called "action Levels" or "Maximum Contamination Levels" (MCLs). The Environmental Medicine section contains MCLs for 50 of the most important chemical contaminants. A list of state environmental authorities are given in the Environmental Law section. These site-specific factors are important to the selections of a feasible environmental technology that can achieve cleanup criteria for a given site. Each contaminated site will have its own unique geographic setting, environmental conditions, and site usage history. The feasible remedial methods must then be analyzed using cost, reliability, and time-to-completion as the comparative criteria.