East Tennessee – (WOKI / WVLT) – The Tennessee Department of Environment and Conservation (TDEC) has issued precautionary fish consumption advisories for two East Tennessee waterways after testing revealed elevated levels of mercury and other contaminants in fish tissue.
The advisories affect Mitchell Branch Stream in Roane County and a section of the French Broad River that stretches through Sevier and Knox counties.
State officials are advising pregnant women, nursing mothers and children to avoid eating the affected fish species entirely. Other individuals should limit consumption to no more than one meal per month.
TDEC emphasized that recreational activities including boating, kayaking, swimming, wading and catch-and-release fishing remain safe and pose no health risk.
Mitchell Branch Stream Advisory
In Roane County, the advisory applies to all fish species in Mitchell Branch Stream due to elevated concentrations of mercury and polychlorinated biphenyls (PCBs).
Testing conducted by Oak Ridge National Laboratory (ORNL) in 2023 found contaminant levels in redbreast sunfish exceeding state precautionary thresholds.
According to TDEC:
- Mercury averaged 0.49 milligrams per kilogram, above the state’s precautionary trigger point of 0.3 milligrams per kilogram.
- PCB levels averaged 0.406 milligrams per kilogram, significantly exceeding the trigger point of 0.047 milligrams per kilogram.
Mitchell Branch is a tributary of Poplar Creek located within the Manhattan Project National Historical Park near Oak Ridge.
French Broad River Advisory
A separate advisory has been issued for black bass species, including largemouth bass, spotted bass and smallmouth bass, caught in the French Broad River.
The advisory covers the river from its confluence with the Tennessee River at Fort Loudoun Reservoir upstream to Douglas Dam.
Fish tissue samples collected by the Tennessee Valley Authority (TVA) and the Environmental Protection Agency (EPA) between 1998 and 2025 found mercury concentrations above state safety thresholds.
Testing showed mercury levels averaging 0.42 milligrams per kilogram, exceeding Tennessee’s precautionary benchmark of 0.3 milligrams per kilogram.
Public Notification Effort
TDEC, which issues fishing and water quality advisories under the Tennessee Water Quality Control Act, says it is working with the Tennessee Wildlife Resources Agency (TWRA) to notify the public and install advisory signs at major access points along both waterways.
Officials encourage anglers to review current fish consumption advisories before consuming their catch.
For a list of affected waters in East Tennessee, please go to: https://www.tn.gov/content/tn/environment/program-areas/wr-water-resources/watershed-stewardship/bacteriological-and-fishing-advisories.html
