Role of uncertainties in protecting ecological resources during remediation and restoration

ABSTRACT

Cleanup of contaminated waste sites is a National priority to protect human health and the environment, while restoring land to productive uses. While there are uncertainties with understanding risk to individuals from exposure, the aim of this study was to focus on uncertainties and complexities for ecological systems, complicated by hundreds of species occupying any remediation site which participate in multiple-interacting food webs. The ability to better predict the effectiveness of remediation in fostering future ecosystems might facilitate remedy selection and improve strategic environmental management. This investigation examined (1) uncertainties in ecosystem processes, (2) uncertainties in exposure from contamination before remediation, and (3) uncertainties during remediation. Two Department of Energy sites Hanford Site and Savannah River Site were used as case studies to illustrate how the uncertainties affect eco-receptors. Several types of ecological, physical, and human dimension uncertainties are defined. Ecological uncertainties include temporal, spatial, individual, developmental, and exogenous types. Physical uncertainties are weather-related, watershed variations, slope/aspect, soil/sediment structure and form, unforeseen events, and temporal patterns. Human dimension uncertainties include current land use, future land use, extractive and non-extractive recreation. The effects of remedial strategies varied between the two sites because Hanford is a primarily arid shrub-steppe ecotype, while Savannah River is a wet forest ecotype. Defining the associated ecological sensitivities and uncertainties and providing examples might help policy-makers, managers, planners, and contractors to be aware of issues to consider throughout planning, remediation, and restoration. Adding ecological uncertainty analysis to risk evaluations and remediation planning is analogous to using safety factors in human health risk assessment.

KEYWORDS:

• Uncertainties
• remediation
• ecosystems
• ecological effects
• Hanford site
• Savannah River site
• Department of Energy

Acknowledgments

We thank many colleagues who have discussed ecological resources, ecological risk and evaluations, and the values Tribes and stakeholders hold for the Hanford Site, as well as several colleagues at the Savannah River Site who worked with us over the years. We especially thank David Kosson and Charles Powers. James Clarke provided useful insights during the review process. The opinions, findings, conclusions, or recommendations expressed herein are those of the authors and do not necessarily represent the views of the U.S. DOE, Rutgers University, Vanderbilt University, and other participating universities.

Additional information

Funding

This study was supported by the Department of Energy (DE-FC01-06EW07053, DE-FG-26-00NT 40938) through the Consortium for Risk Evaluation with Stakeholder Participation (CRESP), at Vanderbilt University, Rutgers the State University of New Jersey, and the U.S. Department of Agriculture (NJ Agriculture and Extension Service, Project 826728, W4045)..