1. Groundwater Contamination by Chlorinated Solvents: History, Remediation Technologies and Strategies

Chlorinated solvents have seen broad usage for a wide variety of purposes, from cleaning of machinery, clothes and electronic parts to use in chemical manufacturing. However, through general dispersal, during normal usage and also as a result of indiscriminate disposal, chlorinated solvents have caused a variety of environmental problems. One such problem of great concern is the contamination of soil and groundwater. This problem became most evident following the passage in the United States of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), or Superfund legislation, in 1980 and the subsequent evaluation of chemical contamination of groundwater. It is now recognized that there are thousands of public and private sites with chlorinated solvent related groundwater contamination problems. Remediation of such sites has been found to be especially difficult and costly. Many potential technical solutions have been developed and applied, often with limited success. Time frames for remediation tend to be long, often measured in decades. It is incumbent upon those responsible for planning, designing and overseeing the remediation of soil and groundwater contamination with chlorinated solvents to fully understand the difficulties and high costs that are likely to be involved, and to have sufficient knowledge of the uses and limitations of the many available technologies that may be applied to a solution. It is highly likely that several technical approaches will be needed together to reach a satisfactory solution that will effectively reduce risks to human health and the environment.