NRDA Practitioners Share Knowledge to Enhance Restoration of Resources Impacted by Hazardous Substances

David Rouse, U.S. Fish and Wildlife Service; Sarah E. Allan, National Oceanic and Atmospheric Administration; Nadia Martin, Industrial Economics, Inc.; and Jeffrey M. Morris, Biodiversity Research Institute

Natural Resource Damage Assessment (NRDA) is a science-based legal process for determining the type and magnitude of injury to public natural resources caused by the release of hazardous substances to define appropriate restoration. In the United States, NRDA may be carried out under different legal authorities, such as the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA, also known as Superfund), Oil Pollution Act (OPA), or others, provided certain criteria are met. These criteria include confirmation that oil or a hazardous substance has been released, a pathway exists between the point of release and a natural resource, and a natural resource has been injured.

The “Tools, Methods, and Approaches for Natural Resource Damage Assessment” session at the SETAC North America 45th Annual Meeting convened a diverse group of practitioners from government, business and academia to explore innovative methodologies for assessing and restoring natural resources injured because of hazardous substance releases. The session featured six platform presentations and three posters, providing valuable information to support the NRDA process, including advancements in tissue residue predictions, insights into injury and restoration, case studies demonstrating innovative assessment approaches, and approaches for developing tribal cultural loss claims.

Advancements in Estimating Contaminant Tissue Residues for Injury Assessment

Amber Stojak with Arcadis introduced a decision diagram designed to help practitioners select the most suitable interpolation methods for addressing spatio-temporal data gaps in sediment datasets. Its practical applications were demonstrated with examples for both temporal and spatial data gaps, and implications for the development of bioaccumulation factors and trophic factors were discussed.

Fabrizio Bonatesta with Abt Global presented on a new trophic magnification model to improve fish tissue residue estimation across trophic levels. His model incorporates bioaccumulation factors and trophic magnification slopes to estimate tissue residues based on sediment concentrations, enabling more accurate characterization of exposure and potential effects across different trophic levels.

Insights into Injury and Restoration

Bridger Creel with the University of Montana highlighted the utility of tree swallows as a sentinel species for monitoring contaminant impacts to aquatic systems due to their ubiquitous nature, link to aquatic food webs, site fidelity, and existing repository of long-term exposure and effects studies. In their presentation, they discussed a tree swallow monitoring program that includes multiple endpoints, such as contaminant tissue residues, reproductive success, and growth metrics. Preliminary data were shared from a selenium-impacted site, illustrating the effectiveness of tree swallows as indicators of contaminant impacts to aquatic ecosystems.

Josh Ackerman with the USGS introduced new mercury toxicity reference values for multiple bird tissue residues and foods that were developed from a series of Bayesian hierarchical meta-analyses and quantified using a benchmark dose framework. The derived dose–response relationships were incorporated into their Bird Mercury Tool, a simplified application that allows users to enter mercury concentrations from most bird tissues and diet to obtain estimations of ecological injury. The application of the new Bird Mercury Tool was showcased in the presentation, where data from an anonymized NRDA case was run through the tool.

Tim Walker with Arcadis proposed a unified framework for constructing matrix population models, aiming to standardize their use in quantification of ecological losses. His poster introduced the Building Block Matrices concept in population modeling and detailed three foundational building blocks for these models: Survival, reproduction and transition, emphasizing the advantages of this standardized approach, like the ease in which the concept can be learned, flexibility, and validation in the literature. An example using this approach was illustrated with a Pacific Coast salmonid population.

Nadia Martin with Industrial Economics, Inc., outlined best practices for conducting streamlined NRDAs. Her framework focused on enhancing the efficiency of NRDA claims to achieve restoration sooner, using established methodologies that clarify the nexus between injury and restoration efforts. Key recommendations included fostering a common understanding of process timelines, employing standardized input values, and ensuring flexibility for site-specific adjustments. She noted that while streamlined approaches might not suit all cases, they have proven effective for less complex sites.

Case Studies Demonstrating Innovative Assessment Approaches

April Reed, an Oak Ridge Institute for Science and Education researcher with the U.S. Environmental Protection Agency, presented a case study on using Bayesian networks for injury quantification at the Little Mississinewa River, Indiana. She summarized a probabilistic injury determination and quantification approach relying on a Bayesian network to quantify injury of a fish community exposed to PCBs. Key advantages included adaptability to new data, capability to incorporate expert knowledge, ability to evaluate spatial variability of injury, and transparent uncertainty evaluation, though challenges such as increased uncertainty with increasing data gaps and the potential large time-commitment required to learn this approach were acknowledged.

Serena Ciparis with the U.S. Fish and Wildlife Service described an incident involving an acute hazardous substance spill in a remote stream that precluded the possibility of a fish kill investigation. Instead, she utilized benthic macroinvertebrate community data to quantify injury, utilizing comparable benthic macroinvertebrate community data collected as part of existing state water quality monitoring programs to establish baseline conditions. A resource equivalency analysis quantified injury and guided restoration planning, underscoring the role of benthic macroinvertebrates as a suitable species group for injury assessments in certain situations.

Cultural Loss Claims

Sherry Kircher with the U.S. Bureau of Indian Affairs discussed methods for developing tribal cultural loss claims, highlighting the commonalities and unique aspects compared to other injury categories. Emphasizing the importance of incorporating indigenous knowledge, she recommended building trust with affected tribes and utilizing culturally relevant data sources, such as community interviews and cultural activity resources.

Conclusion

This session provided a valuable platform for NRDA professionals to exchange ideas and methodologies aimed at improving the precision and efficiency of ecological and cultural use injury assessments. Furthermore, some information provided has application beyond NRDA and could support various aspects of environmental remediation and risk assessment. Throughout the presentations, the overarching goal of restoration was emphasized, illustrating the critical need for early identification of restoration concepts to inform future assessment activities. This symposium built on previous NRDA sessions at SETAC North America annual meetings by fostering a collaborative environment for practitioners to continue to share insights.

Future sessions could focus on specialized topics, such as new approach methodologies in NRDA, injury assessments related to certain per- and polyfluoroalkyl substances, streamlined approaches for small spills, and restoration scaling approaches and methods.

Authors’ contacts: [email protected], [email protected], [email protected] and [email protected]