Mercury releases in Oak Ridge, Tennessee

THE EVENT: Contamination of air and water by mercury leaked from a nuclear weapons plant in Oak Ridge, Tennessee

DATES: 1950s; discovered in December 1981

After researchers discovered that mercury from a nuclear weapons plant had contaminated air and water in Oak Ridge, Tennessee, subsequent study of the contamination raised questions about the methods used to determine the risk of toxic pollution to humans.

In December 1981, Stephen Gough, a biologist employed at Oak Ridge National Laboratory, tested a number of the plants growing near East Fork Poplar Creek and found that they contained a high amount of mercury. Because the creek was near the US Department of Energy’s (DOE) Y-12 plant, where nuclear bombs had been built in the 1950s, the possibility was raised that a large amount of mercury had been released into the from the plant over the intervening years.

During 1982 the DOE commissioned a study to determine how much mercury had been released. The researchers discovered that an estimated 215,000 kilograms (475,000 pounds) had been released into the creek and that another 907,000 kilograms (2 million pounds) were unaccounted for. The DOE report on the study was made public on May 17, 1983, after a small local newspaper and the Tennessee Department of Health and Environment requested to see the report under the Freedom of Information Act. After a public hearing on June 11, 1983, the DOE was reprimanded by the Science and Technology Committee of the US House of Representatives on November 3, 1983. It was also ordered to assess the risks to human health of the mercury at Oak Ridge and to produce an accurate estimate of how much mercury had been released into the creek and the atmosphere.

The greatest to human health from mercury comes from mercury in the methylated form. A problem of this type occurred in Minamata Bay, Japan, in the 1960s, when many people who ate seafood from the methyl mercury-contaminated bay developed symptoms of mercury poisoning. The DOE claimed that the mercury at Oak Ridge was not methylated but in elemental form, so the risk was minimal. The DOE also claimed that the mercury was released below the public drinking-water intake and that the mercury traveled downstream before into the earth, where it was trapped by a layer of shale before entering the groundwater. Another danger for humans from mercury is the consumption of contaminated fish; because the fish in Poplar Creek were determined to have twice the level of mercury deemed safe by the US Food and Drug Administration (FDA), fishing in the creek was banned.

A report released by the DOE in 1997 stated that 127,000 kilograms (280,000 pounds) of mercury had entered the East Fork Poplar Creek and that 33,000 kilograms (73,000 pounds) of mercury had entered the atmosphere over several years, with peak years being 1957 and 1958. The study also estimated vegetable and milk production and consumption near the creek during critical years, since the airborne mercury could have contaminated gardens, crops, and grass eaten by cattle. The mercury in the soil was determined to be mercuric sulfide, a stable compound that was not likely to migrate to centers of population.

The DOE’s report concluded that small doses of mercury had been ingested by local residents during the decades following 1950 but that such low levels did not pose a health risk. Controversy followed the report, as health experts asserted that individuals react to mercury ingestion in varying ways and that immune disorders and diseases found in people who lived in the Oak Ridge area could be results of the mercury release.

Bibliography

Eisler, Ronald. Mercury Hazards to Living Organisms. Boca Raton, Fla.: CRC Press, 2006.

Johnson, Charles W., and Charles O. Jackson. City Behind a Fence: Oak Ridge, Tennessee, 1942-1946. Knoxville: University of Tennessee Press, 1981.

"Oak Ridge Team Makes Headway on Mercury Treatment Facility." Office of Environmental Management, Mar. 28, 2023, www.energy.gov/em/articles/oak-ridge-team-makes-headway-mercury-treatment-facility. Accessed 21 July 2024.

Olwell, Russell B. At Work in the Atomic City: A Labor and Social History of Oak Ridge, Tennessee. Knoxville: University of Tennessee Press, 2004.