Abstract
•Remediation includes activities using personnel and equipment in combinations.•Recovery depends on the density, severity, and length of remediation activities.•Recovery depends on whether an initiating event was natural, anthropogenic, or both.•Ecosystems may recover faster with natural events than with anthropogenic ones.
The United States faces a massive task to clean up legacy nuclear, chemical, and structural wastes remaining from the Cold War, and industrial and hazardous wastes, as well as the decommissioning and spent nuclear fuel removal of numerous commercial nuclear facilities nearing the end of useful life. Many sites are on or adjacent to open spaces or waterbodies of varying ecologic quality and utility. Assessing the risks to ecological resources is thus a challenging task that usually involves consideration of the direct risk to these receptors from the ongoing exposure to the contamination before remediation. Here we address impacts during and after remediation. Different remediation types and activities (digging and removal, containment/capping, decommissioning/demolition, pump and treat, in situ treatment), as well as transportation and ultimate disposition can have direct ecological effects including disruption, displacement and death to plants and animals on the remediation site and on surrounding areas. For each type of remediation, two aspects require consideration: the functional aspects of remediation (how many and what types of people, cars, trucks, hoses, heavy equipment, drilling rigs are on the remediation site), and initiating events that can interact with remediation causing harm to ecologic receptors. In this paper we 1) describe initiating events and functional remediation, 2) provide a conceptualization of interactions between them, and 3) examine the types of effects that result from natural and anthropogenic stressors due to the interactions between functional remediation and initiating events. Initiating events are low probability, high consequence events, including “natural” disasters (e.g. earthquakes, hurricanes, floods, fires) and anthropogenic (building collapses, structural failures) events, that start or cause a response in species or ecosystems. Functional remediation includes the elements of remediation that occur in combination under different remediation types. Interactions between the two may be overlooked when determining the factors to consider in developing bioindicators, assessment tools, and monitoring plans to protect human and ecological health. Each can exacerbate the ecological impacts of the other. We use the Hanford Site in Washington State as a case study, but the principles are broadly applicable.