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Ecological health of East Fork Poplar Creek continues to improve
The ecological health of the East Fork Poplar Creek continues to improve.
East Fork Poplar Creek, which originates within the Oak Ridge Y‑12 National Security Complex before flowing through the City of Oak Ridge, continues to recover from its Cold War legacy of contamination.
The ecological health of the stream has improved significantly, as shown by substantial increases in the number and abundance of fish and benthic macroinvertebrate species, especially those that are more sensitive to pollution.
The most recent detailed study of the status of the creek, conducted by researchers from Oak Ridge National Laboratory (ORNL) is available. While this report has information from the 2005 study, the positive trends continue to show incremental changes. There have been no significant negative changes in the status of the creek since this study was completed.
The ongoing recovery of East Fork Poplar Creek can be largely attributed to the numerous environmental improvement projects, pollution prevention measures, and remedial actions undertaken at Y‑12 since the mid 1980s. For many years there has been a special emphasis at Y‑12 to reduce the impact on receiving streams of legacy contaminants, particularly mercury and polychlorinated biphenyls (PCBs).
Major projects to improve the ecological health of the creek include:
- constructing waste water treatment facilities,
- rerouting drains,
- capping waste burial sites,
- implementing pollution prevention measures, and
- implementing Best Management Practices.
All the actions have resulted in steady improvements in water quality.
One result of the various actions taken at Y‑12 has been a significant decrease in mercury entering East Fork Poplar Creek. The use of metallic mercury in the 1950s and 1960s resulted in the contamination of the soil, buildings, storm drain network, and ground and surface water.
In the upper reaches of the stream, water-borne mercury dropped to less than one-fourth the levels observed in the late 1980s and early 1990s. That level dropped even lower before stabilizing in the early 2000s. Recently, the start-up of a new mercury treatment facility has contributed to an additional decrease in water-borne mercury.
Since the mid 1980s, ORNL researchers associated with the Y‑12 Biological Monitoring and Abatement Program (BMAP) have monitored the health of stream fish and benthic communities in East Fork Poplar Creek. This long-term biological monitoring program has been very successful over the years in documenting the effects of Y‑12 remedial actions in restoring the ecological health of the stream and indicating areas where further improvement is needed. These data are reported to the Tennessee Department of Environment and Conservation and other regulatory agencies, as stipulated in the National Pollutant Discharge Elimination System permit that became effective in May 2006.
A significant milestone in the ongoing ecological recovery of East Fork Poplar Creek has been the marked improvement in the health of the fish and benthic invertebrate communities in the stream. The number of different species found in East Fork Poplar Creek, including those that are considered pollution-sensitive, has increased throughout the stream. In fact, nearly as many pollution-sensitive species can now be found in the lower reaches of East Fork Poplar Creek as in local reference streams.
Although the pronounced decrease in water-borne mercury and the improvement in the biological communities of East Fork Poplar Creek are welcome news, challenges to further recovery in the creek remain. For example, mercury continues to be elevated in East Fork Poplar Creek fish despite significant reductions of mercury concentrations in water. As with other mercury contaminated sites across the nation, reducing mercury concentrations in fish to acceptable levels will continue to be a challenging task.
Likewise, achieving further water quality improvements in the upper reaches of the stream, where there continue to be impacts to fish and benthic communities relative to other local streams, is a challenge given the size and complexity of the industrial and urban landscape and the difficult remediation of remaining legacy contamination. But the challenges seem less insurmountable than they did many years ago.
With effective environmental programs at Y‑12, such as the BMAP and Environmental Officer Program, which involves every organization within the site in achieving environmental objectives, and with various large-scale environmental remediation and decontamination and decommissioning activities planned over the next few years, further recovery of the creek is anticipated. Sampling and monitoring of East Fork Poplar Creek under the BMAP will continue to provide relevant information regarding conditions in the stream.
Additional information regarding the monitoring of this stream can be found in the Oak Ridge Reservation Annual Site Environmental Report.