Despite nearly 40 years of intensive efforts in the United States as well as in other industrialized countries worldwide, restoration of groundwater contaminated by releases of anthropogenic chemicals to a condition allowing for unlimited use and unrestricted exposure remains a significant technical and institutional challenge.
Recent (2004) estimates by the U.S. Environmental Protection Agency (EPA) indicate that expenditures for soil and groundwater cleanup at over 300,000 sites through 2033 may exceed $200 billion (not adjusted for inflation), and many of these sites have experienced groundwater impacts.
One dominant attribute of the nation’s efforts on subsurface remediation efforts has been lengthy delays between discovery of the problem and its resolution. Reasons for these extended timeframes are now well known: ineffective subsurface investigations, difficulties in characterizing the nature and extent of the problem in highly heterogeneous subsurface environments, remedial technologies that have not been capable of achieving restoration in many of these geologic settings, continued improvements in analytical detection limits leading to discovery of additional chemicals of concern, evolution of more stringent drinking water standards, and the realization that other exposure pathways, such as vapor intrusion, pose unacceptable health risks. A variety of administrative and policy factors also result in extensive delays, including, but not limited to, high regulatory personnel turnover, the difficulty in determining cost-effective remedies to meet cleanup goals, and allocation of responsibility at multiparty sites.