April 20, 2010

Groundwater Cleanups – What If Drinking Water Standards Cannot Be Met?

Posted on April 20, 2010 by Charles Tisdale

EPA began the CERCLA program in 1980 with the view that all sites could be remediated to stringent cleanup standards, including drinking water standards for contaminated groundwater. The primary remedy selected for groundwater contamination was extraction and treatment. Consent Orders typically required groundwater remediation to be conducted for 30 years, if necessary, to achieve drinking water standards.

            New technologies are being used to remediate groundwater and there has been much progress. However, there are still sites where it is clear that drinking water standards will not be met in 30 years and where the cost of continued treatment produces only limited reduction of contaminant levels.  CERCLA is 30 years old and there are many case histories to use in the evolution of policies developed when the program began. 

            EPA provides relief for contaminated groundwater that exceeds drinking water standards through technical impracticability waivers, alternative concentration limits and monitored natural attenuation. However, these mechanisms have not provided the relief that many expected at sites where the facts show that standards will not be met.

            EPA and states have changed their original position with respect to cleanup of soil to stringent limits in all locations. Environmental agencies now look at issues of risk and actual exposure to contaminated soil rather than theoretical exposure. Some states have developed new policies with respect to groundwater remediation which include more thorough considerations of risk and actual exposure.

            There is growing concern over the availability of water, even in areas of the United States which have not experienced water supply problems in the past. Thus, there are strong reasons for remediating contaminated groundwater to drinking water standards. However, there are a number of sites where long term remediation will not achieve drinking water standards.

            Is there a need for new policies and procedures for sites where contamination levels can be reduced but drinking water standards will not be achieved? What elements are appropriate for a new policy? Should there be a procedure for environmental agencies to restrict the use of groundwater where there is no risk to actual drinking water supplies? Should EPA provide guidance to encourage the use of technical impracticability for these sites? Should the agency consider a policy to control the plume of contamination rather than requiring drinking water standards to be met throughout the contaminated groundwater?

Tags: Water


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