Fourteen years since the Super-fund program was launched, the National Research Council has issued a cautionary word about cleaning up mismanaged waste: It's not always going to work.
With current technologies, it is impracticable to remediate groundwater to health-based goals at a large number of sites, according to a Committee on Groundwater Cleanup Alternatives report which was released last September. Even with enhanced pump-and-treat methods such as air sparging and in-situ bioremediation, the group contends that it will not be possible to fully restore sites with severe contamination. As a result of the report, legislators in the House and Senate have proposed Superfund language to give EPA more flexibility when selecting cleanup remedies.
The committee recommends government regulators establish consistent mechanisms for classifying sites so that groundwater cleanups can proceed and actions to contain contamination can be initiated where needed. The classification system would group sites according to the following criteria:
* Possible to clean up. This includes sites where it should be possible to meet drinking water standards with existing technologies;
* Potential for clean up. This includes sites where cleanup may be possible as technology improves; and
* Little potential for clean up. This includes sites where attainment of health-based standards is highly unlikely within a reasonable timeframe (decades).
While political considerations may require health-based cleanup standards to be retained as a long-term national goal, the committee suggests adopting less-stringent cleanup standards as interim objectives for the second and third categories because of current technological limitations.
Public health is not necessarily endangered when full cleanup isn't possible, said Committee Chairman Michael Kavanaugh of Environ Corp., Emeryville, Calif. Systems can contain the contamination at sites where full remediation is not achieved, he said. Also, institutional controls such as deed restrictions can be undertaken and point-of-use treatment can ensure that drinking water is safe, Kavanaugh added.
To oversee the large number of sites that cannot be completely cleaned up, the committee has called for an institutional structure that will last several generations.
While it may not be possible to return groundwater to drinking water standards, less stringent goals can be achieved. According to the panel, at most sites it is possible to "clean up areas containing dissolved contaminants and install containment systems around areas with dissolved contaminants that cannot be removed."
A researched opinion on how many sites can or cannot be cleaned up does not exist, Kavanaugh said. However, he estimates that 80 percent of the larger sites are never likely to have a portion of the aquifer remediated.
According to Kavanaugh, the classification system won't waste money by trying to do something that can't be done. It will be recognized that remediation is not possible at sites meeting certain criteria. As a result, Kavanaugh notes, responsible parties can institute containment actions immediately and futile cleanup efforts can be avoided.
To encourage the development of innovative cleanup techniques, the committee has proposed assessing an "infeasibility fee" at sites where cleanup is not currently possible. The money collected would fund applied groundwater research or help to defray costs when an innovative technology does not achieve the intended goal.
To ensure that obstacles to meeting drinking water standards are recognized as soon as possible, the committee has asked EPA to revise its guidelines for site characterization and to require the:
* Collection of information on the vertical and horizontal extent of groundwater contamination;
* Approximate locations of long-term contamination sources;
* Hydrogeological features that could affect cleanup; and
* Other data for estimating a site's restoration potential.
A panel review of 77 sites operating pump-and-treat systems found that only eight sites have been cleaned up, although some may eventually reach that goal. Based on contaminant chemistry and hydrogeology, the committee placed the sites in four categories depending on the level of difficulty of cleanup, with one rated as easiest to clean up and four as the most difficult.
Two of the 77 sites were rated Category One and only one of these has been cleaned up. Goals at 10 of the 14 sites in Category Two have yet to be met, while remediation has been achieved at three of 29 sites in Category Three; all three were contaminated with gasoline. Cleanup goals have not been achieved at any of 42 sites in Category Four.
The panel noted that a single site may contain subregions with various levels of remediation difficulty.