The Tennessee Department of Environment and Conservation (TDEC) has announced a precautionary fish consumption advisory due to mercury on Dale Hollow Reservoir in Clay, Pickett, and Overton counties.
In the fall of 2019 and spring of 2021, TDEC and the Tennessee Wildlife Resources Agency (TWRA) collected fish tissue data on Dale Hollow Reservoir where fish were analyzed for EPA priority pollutants (metals and organics). Based on the fish tissue results, a precautionary fish consumption advisory is being issued for walleye and black bass species (largemouth, spotted, and smallmouth) in the reservoir.
TDEC advises that pregnant women, nursing mothers, and children avoid eating the fish species included in the advisory and that all others limit consumption to one meal per month. Other recreational activities such as boating, kayaking, swimming, wading, and catch and release fishing carry no risk.
ìWe provide these advisories so the community can make informed decisions about whether or not to consume the fish they catch,î said TDEC Deputy Commissioner Greg Young. ìUnlike ëdo not consumeí advisories that warn the general population to avoid eating fish from a particular body of water altogether, precautionary fish consumption advisories are specifically directed to sensitive populations such as children, pregnant women, nursing mothers and those who may eat fish frequently from the same body of water.î
These studies documented that in walleye and black bass species mercury levels were above the trigger of 0.3 mg/kg (parts per million), establishing a clear basis for a precautionary fish advisory for the entirety of Dale Hollow Reservoir.
TDEC considers the source of mercury in Dale Hollow Reservoir to be atmospheric deposition. According to the EPA, atmospheric deposition due to the global burning of coal is the most frequent reason for elevated levels of mercury in fish.
TDEC will post warning signs at primary public access points and will work with the TWRA and United States Army Corps of Engineers to communicate this information to the public.
About Fish Consumption Advisories
The Tennessee Water Quality Control Act identifies the commissioner of the Department of Environment and Conservation as having the authority and responsibility to issue advisories for either water contact hazards like pathogens or excessive health risks due to the accumulation of contaminants in fish or shellfish. Tennesseeís General Water Quality Criteria provide additional guidance regarding the conditions under which advisories may be warranted.
There are two types of fish consumption advisories issued by TDEC based on the levels of contaminants present in fish tissue. ìDo not consumeî fishing advisories are issued when levels of contaminants in fish tissue would represent a threat to the general population. Precautionary advisories are issued when contaminant levels are lower but would still pose a risk to sensitive subpopulations such as children, pregnant women, nursing mothers and those who eat fish frequently from the same body of water.
Where new advisories have been issued, TDEC will immediately begin the process of putting up signs at primary public access points. TDEC works in partnership with the TWRA to communicate information about fishing advisories.
For a complete listing of Tennesseeís current fishing advisories plus additional information about the advisory issuance process, visit: https://www.tn.gov/content/dam/tn/environment/water/watershed-planning/wr_wq_fish-advisories.pdf.
An EPA website has additional information about mercury at: http://www.epa.gov/fish-tech/epa-fda-advisory-mercury-fish-and-shellfish.