is spreading and there is the chance that MCLs for the contaminants of concern will be lowered in the near future. This will make wellhead treatment, currently estimated by one water utility to be $128 million, significantly more expensive than plume remediation (estimated to be about $91 million, by the same utility) (Massapequa Water District, 2011). State regulatory authorities have come up with different cost estimates and continue to recommend wellhead treatment over plume remediation because some wells are already contaminated and will have to be treated in perpetuity. It is too soon to tell how the dispute over the proper remediation strategy at the Navy/Northrop-Grumman plume will be resolved.
Sites with subsurface contamination by hazardous materials present economic challenges to responsible parties and people and businesses affected by the contamination. When contamination remains in place above unrestricted use levels, there are direct, out-of-pocket costs of controlling contamination. There are also opportunity costs such as forgone revenue from not being able to use the contaminated site and nearby areas for other endeavors.
Figure 5-1 provides a stylized example of costs associated with a contaminated groundwater site. “Services under baseline” represents water quality in an aquifer absent of contamination. Suppose a release of a hazardous substance occurs at time T0. In this example, it is assumed that 25 percent of the groundwater remains accessible for use with contaminant levels below MCLs, i.e., pumping can continue in some parts of the aquifer. Once contamination occurs, the Recovery Path represents improvements in groundwater quality due to natural attenuation of the hazardous substance.
A treatment program will enhance recovery and is indicated by the Recovery Path with Remedial Action in Figure 5-1. For simplicity, the recovery path begins at time T0, although this would only be the case where a contaminant release was instantaneously known and remediation efforts were initiated immediately to control damages. Losses in groundwater services after remediation are shown by the shaded area and can only be fully revealed over time. Potentially responsible parties can compensate affected parties for residual losses (shaded area) or they can provide equivalent services known as compensatory restoration (dotted area). Compensatory restoration is typically designed so that the benefits of the compensatory restoration just offset the loss (the dotted area just equals the shaded area). Note, the hatched area constitutes losses that occurred prior to the implementation of CERCLA; some trustees submit claims for these losses and others just submit claims for losses subsequent to the implementation of CERCLA.