Contaminated Department of Energy facilities and ecosystems: weighing the ecological risks

With the ending of the Cold War, the United States and other industrialized nations are faced with the monumental task of cleaning up hazardous waste sites that were created over a 50-year period. While many factors enter into the cleanup decisions of managers of hazardous waste facilities, such as at Department of Energy sites, risk assessment plays a central role in evaluating the hazards to ecosystems and humans. Often risk from hazardous facilities is determined by identifying the risks to people, or immediate ecosystems, without regard to the size or magnitude of the surrounding ecological system or of the receptors within that system. Identifying the types of systems for contaminated systems would add immeasurably to evaluating the risks from those hazards. Using the Department of Energy (DOE) facilities as examples, it is suggested that there are three major types of systems that should be considered: (1) contaminated buildings and other facilities, (2) buffer zones that immediately surround contaminated facilities, and (3) relatively pristine or uncontaminated ecosystems that surround or are adjacent to the contaminated facilities. The relative ecological risks from remediation and restoration on these three different types of systems vary markedly, in terms of immediate effects, long-term effects, and the potential for complete recovery. Remediation on most systems containing predominately buildings and other facilities entails very little ecological risk, except for disruption of nearby ecosystems from construction and transport of materials offsite. Remediation on buffer zones, however, might cause considerable ecological damage if these systems have already undergone partial recovery, are large, and will experience physical disruption during remediation. Remediation that impacts relatively pristine or uncontaminated sites can cause major disruptions to ecosystems well beyond the value, in terms of reduced human health risk, of the restoration itself, and recovery may never be complete. Although this analysis does not consider the risks to workers from remediation, such risks should be added to the potential harm to functioning ecosystems from remediation at nearby contaminated sites. The effects of remediation on all three types of systems should be balanced when making remediation decisions. The newly proposed integrator operable unit, which surrounds the contaminated sites (operable units), and includes all other areas, provides an additional framework for considering risk, remediation, and long-term stewardship on Department of Energy lands.