Source:  EM Update | Vol. 11, Issue 5; Contributor: Ben Williams | February 5, 2019

Oak Ridge National Laboratory scientists gather sampling data from the East Fork Poplar Creek.

Through support from DOE’s Oak Ridge Office of Environmental Management (OREM), researchers at Oak Ridge National Laboratory’s (ORNL) Aquatic Ecological Laboratory are advancing the understanding of mercury’s impact on fish, wildlife, and streams.

For more than 70 years, scientists at this DOE Office of Science national laboratory have been at the forefront of environmental research and discovery, including leading some of the longest-running studies of small streams in the world.

Now, they have partnered with OREM to conduct remediation research, including assessments of remedial performance and ecosystem recovery. They also support EM’s goal of developing new technologies and remedial solutions for future mercury cleanup in soil, sediments, and creeks.

Working together, EM and the Office of Science are gaining a deeper understanding of the local environment and finding answers to aid cleanup in Oak Ridge.

“The science we are learning is helping direct management actions, but it is also revealing less intrusive remedies where we can manipulate the ecology to address contaminated areas without incurring big cleanup costs,” Aquatic Ecology Group Leader Mark Peterson said.

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Artificial intelligence assists researchers by identifying invertebrate community structures within the images taken of water samples.

For example, native freshwater mussels have shown the ability to significantly improve water quality. They remove inorganic mercury from the water and may prevent the element from entering the food chain and being converted into its most hazardous form — methylmercury.

The group is also making progress identifying the most effective sorbent materials to extract mercury from the East Fork Poplar Creek banks downstream from the Y-12 National Security Complex. This research enables OREM to find new tools and approaches that could be more effective, reduce costs, and accelerate cleanup schedules to address the site’s complex mercury challenge.

“This partnership between EM and the Office of Science highlights the advances and benefits that are possible when we pair the resources and incredible talent within these two vital DOE programs,” OREM Manager Jay Mullis said.

Mercury cleanup is EM’s highest priority at Y-12. Operations used large amounts of mercury during the 1950s and 1960s, and a portion was lost into the environment. OREM is constructing the Outfall 200 Mercury Treatment facility as part of its cleanup approach, which will help fulfill regulatory commitments to reduce mercury levels in the creek and enable large-scale cleanup and demolition to start at Y-12.

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Researchers measure mercury levels of fish in the laboratory before returning them to the East Fork Poplar Creek.

The ORNL scientists are using sampling methods that bring in more data on the levels of organic mercury or methylmercury in the fish. Researchers collect fish from the creek, measure their mercury levels and growth rates in the laboratory, and return them to the creek. If a fish is caught again, team members can compare mercury concentrations to gauge trends and how fish respond to various changes in the watershed.

OREM is continuing this strong partnership and funding an expansion of the Aquatic Ecology Laboratory that will open later this year. The expansion will allow mercury-contaminated stream water to flow through the facility so researchers can test mercury removal technologies in flowing water in a controlled laboratory setting.