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Radiological Results

In early January 2009, the department’s Division of Remediation collected 29 soil and ash samples in response to the TVA ash slide near Kingston. Two of the ash samples were collected from TVA’s ash retention pond. Two control samples were collected in or adjacent to Roane County Park. The rest of the samples were collected from private properties in the affected area.

The samples were analyzed at the State Laboratory for gross alpha, gross beta, and gamma spectroscopy. The error for the data resulting from the gross alpha and gross beta analyses is reported at the two sigma (95%) confidence level, while the error for the data from the gamma spectroscopy analyses is reported at the one sigma (68%) confidence level. The specific error for each sample analysis is included in the laboratory data sheets posted on this site. Gross alpha and gross beta analyses are indicative of non-specific radioactivity in the samples, while the gamma spectroscopy analyses are more useful in identifying and quantifying the concentrations of specific radionuclides in the samples.

A review of the data indicates that four of the sample analyses identified slight concentrations of cesium 137, which is commonly observed in the environmental samples as a result of the “fallout” that occurred from historical atmospheric nuclear weapons tests. All of the samples contain naturally occurring radionuclides.

One example is potassium 40, which is ubiquitous in the natural environmental. Slightly over 1/10 of one percent of all the potassium in the world is potassium 40. The other naturally occurring radionuclides in the samples are descended from (or result from) the uranium and thorium found naturally in the earth’s crust.  Assuming these naturally occurring radionuclides are at secular equilibrium in the samples, the bismuth 214 concentrations (supported by the lead 214 concentrations) are excellent indicators of the radium 226 concentrations in the samples. Likewise, actinium 228 concentrations (supported by lead 212, bismuth 212 and thallium 208 concentrations) are excellent indicators of the radium 228 concentrations in the samples.

The concentrations of radium in all samples were typical of concentrations normally measured in soil and coal ash. To put this data in perspective, all samples contained significantly less radium than the average concentrations typically found in phosphate fertilizers.

Lab Results Worksheet

Lab Results - Jan. 6, 2009

Lab Results - Jan. 7, 2009

Lab Results - Jan. 12, 2009