The ISC approach outlined in this guidance includes a process for selecting and applying new tools and approaches to characterize sites contaminated by DNAPLs. The science supporting these technologies and approaches is based on quantifying how geology, chemistry, and hydrogeology interact to influence contaminant transport in rock, soil, sediments, and groundwater. These data are collected at a resolution adequate to reduce the uncertainty of contaminant fate and transport to an acceptable level for all parties involved in the characterization of a site. This new ISC approach allows more detailed and representative interpretations without what has been traditionally referred to as data gaps from conventional limited data investigation techniques. It should therefore follow that regulatory performance and remedies implemented to protect human health and the environment would be greatly improved through the application of these investigative strategies and technologies. Stakeholders are likely to embrace these tools and analysis techniques because they are specifically designed to better characterize and define contaminated sites to more effectively clean them up.
The ISC approach allows administrative agencies to compel more protective and cost-effective remedies that do not involve loss of public groundwater resources. It also helps to reduce the danger from direct contact, ingestion, and indoor inhalation pathways. With the new fate and transport concepts and characterization methods/tools, stakeholders can expect to sustain resources, cost-effectively remediate sources, and prevent the loss of regional aquifer systems due to failed remedies. The ISC approach aids in sustainability to balance environmental, economic, and social stakeholder concerns (ITRC Green and Sustainable Remediation, 2011, Table 3-2
Poor remedial decisions, based on limited data, have put tremendous long-term economic burdens on communities due to loss of property values, lower development potential, institutional restrictions on aquifers, and long-term subsurface contamination. Quite often, the aesthetic quality of an aquifer is diminished on a long-term basis downgradient of contaminated sites, which essentially makes the aquifer unusable for domestic water supplies and much more expensive to treat for municipal water supplies. These treatment costs are often passed on to the individual property owner and the community.
The ISC approach promotes targeted remediation and reduction of source mass, which will immediately reduce risk and the long-term remediation costs incurred by remedies that proceed with little or no source control. The stakeholders desire this approach as it will minimize the loss of groundwater through failed remedies and institutional controls, and it will reduce the economic loss of development potential of large tracts of land.
Improved site subsurface characterization will lead to more appropriate remedial decisions and reduce the damage to precious groundwater resources. Thus, the proper use and application of the approaches and technologies presented in this document will lead to greater protection of human health and the environment by ensuring that groundwater and other natural resources critical to health, commerce, economic vitality, and quality of life continue to be available for future generations.
The proper use and application of this approach, as viewed by stakeholders, should promote more protective and proactive remedies at many sites that require periodic assessment of their protection of human health and the environment according to state and federal law and regulation. Stakeholders openly embrace this approach when it is objectively presented and tied to remedial actions objectives that restore aquifers, protect future groundwater resources, and reduce human health and environmental risk.
The ISC approach is clearly capable of providing information that can help determine whether an existing remedy is protective of human health and the environment, whether financial resources are being wasted in the long term on non-cost-effective remedies, and if source control or a multitude of other cost-saving actions can be implemented.
Both public- and private-sector monetary resources should focus on returning resources to a useful and economically productive status. The current regulatory model of restricting the use of and access to resources (that is, institutional controls) can be a long-term stigma to the community, and may even prevent the return of the community to economic prosperity. Protection of human health and the environment go hand-in-hand with economic viability and community prosperity. There is no need to sacrifice either of these goals to achieve a cost-effective and successful remedy.
The public trust has been shaken by inadequate site characterizations and extensive use of risk-based decision making to justify large-scale, long-term natural attenuation remedies for aquifers. In many cases, the traditional approach to characterization and decision making at DNAPL sites has led to non-effective remedies, allowing for the long-term destruction of groundwater resources, and the implementation of institutional controls that restrict the use of regional and local groundwater resources. Aquifers have been taken from current and future generations unnecessarily in many instances. In short, the public has been waiting for a more proactive approach to cleaning up contaminated sites.
Source control and proactive remediation is a foreseeable outcome of the proper use of ISC. The ISC approach should lead to remedial decisions that are protective of human health and the environment, including natural resources, and that gain the trust and support of all stakeholders.