Sliding scales for assessing and communicating human and ecological risks and complexities for restoration, remediation crises, and decisions.

Many lands were degraded or destroyed by human activities, including contamination from industry and military facilities. The United States and other industrialized counties have legacy wastes remaining from the Second World War, the Cold War, and industrialization. There is increasing need to return degraded land to suitable future land uses, including ecological parks and preserves. This paper proposes a conceptual model of the different levels of information needed to understand the risk to human health, the environment, and ecological resources. I propose a four-part approach: 1) general model for assessing ecological resources, 2) model for assessment needed for remediation or restoration projects, 3) a sliding scale, conceptual model for causes, events, and sources that lead to exposure and risk, and 4) an additional step that includes environmental justice (equity, diversity and inclusion) as a necessary consideration of traditional exposure assessment. While the factors involved in ecological risk assessment are well established, the combination of human health, ecological health, and environmental justice determining risk for remediation or restoration projects is not. Major factors useful for human health, environmental, and ecological evaluation include causes, events (earthquakes, accidents, chemical releases), sources, exposure, and informational challenges, as well as barriers to exposure. I propose that exposure through an environmental justice (diversity, equity, and inclusion) lens should be a key component of risk assessment. Each of these factors involves a sliding scale or continuum that must be considered in evaluating risk and communicating with the regulators, resource trustees, land managers and the public. The conceptual model also serves as a template for obtaining information about the environment that will be useful for communicating the importance of different risk factors. The model was developed for consideration of remediation on Department of Energy lands, it can be applied more broadly to other projects.