ABSTRACT
Cleaning up the environment once it becomes contaminated is expensive and time consuming. A sad and disturbing fact is that sometimes when the environmental becomes contaminated, any amount of financial resource or technology will not restore the environment to precontamination levels. Examples include the Exxon Valdez incident in Alaska, Deep Water Horizon incident in the Gulf of Mexico, numerous sites where groundwater becomes contaminated with CVOCs or hexavalent chromium, and PCBs in sediments of large rivers such as the Hudson River in New York and the Willamette River in Oregon. Therefore, in most of these instances, the contamination must be managed through others means so that the spread of contamination is halted or minimized.
Under most scenarios, contaminants released into the environment require clean up. However, as stated above and as we shall discover, typical remediation does not result in returning the affected area(s) or media to precontamination levels. Remediation of contamination is typically conducted to specific targets for each chemical of concern and are based on ecological and human risk. Remediation goals can be site-specific or to generic standards established by the appropriate regulatory agency.
The USEPA estimates that more than 100 billion dollars is spent each year investigating and remediating contaminated sites just in the United States. Estimates on the number of sites remediated or under remediation total over 1 million sites just in the United States. In addition, there are an additional 500,000 to 1 million abandoned industrial facilities or brownfield sites that are waiting to be investigated. This is because a cost estimate to investigate and remediate brownfield sites has not been conducted. Most of these abandoned industrial sites are located in urban areas of the United States. The majority are located in the 27 urban areas listed in Chapter 2. These sites have some degree of contamination and will require some degree of assessing risk or remediation before they can be redeveloped. Thus, it is likely that the environmental costs to investigate and remediate sites of environmental contamination in United States will exceed the latest available USEPA estimate of $250 billion.
Described in this chapter are some of the more common remedial technologies for soil, groundwater, surface water, sediment, and air. As with any successful remedial strategy, controlling the source of contamination is critical for achieving the objective. If controlling or eliminating the source is not achieved, any remedial strategy will fail because re-contamination will occur.
