None of the radionuclides detected in samples collected during the first quarter of 2011 could be directly linked with INL Site activities.  During the second half of March, fallout was detected from the Fukushima nuclear accident in Japan. Levels of detected radionuclides were no different than values measured at other locations across the western United States. All detected radionuclide concentrations were well below guidelines set by the U.S. Department of Energy (DOE) and regulatory standards established by the U.S. Environmental Protection Agency (EPA) for protection of the public. 

Media

Sample Type

Analysis

Air

Filters

Gross alpha, gross beta

No statistical differences were noted in either gross alpha or gross beta data on quarterly and monthly comparisons.  During two weeks, gross beta concentrations were statistically higher at boundary locations than distant locations. No result exceeded the DCG for gross alpha or gross beta activity in air.

Gamma-emitting radionuclides, select actinides (241Am, 238Pu, and 239,240 Pu), 90Sr

Selected weekly filters were analyzed by gamma spectrometry to measure fallout from the Fukushima accident in Japan. Five manmade gamma-emitting radionuclides were found during the week of March 23 and two were found during the week of March 30. Cesium-137 was found on all quarterly composites and Cesium-134 was detected nearly all composites. No 90Sr were detected. Final actinide results were not yet available.

Charcoal Cartridge

Iodine-131

Iodine-131 from Fukushima was reported on all charcoal cartridge batches during the weeks of March 23 and March 30. The highest result was approximately 0.1 percent of the DCG for 131I.

Atmospheric Moisture

Liquid

Tritium

A total of nine samples were collected.  Six of these samples had tritium results greater than the 3s uncertainty. No sample result exceeded the DCG for tritium in air. Results were consistent with historical measurements.

Precipitation

Liquid

Tritium, gamma-emitting radionuclides

Eleven results for samples collected were available.  Two of the results were greater than the 3s uncertainty.  The concentrations were consistent with those reported across the region by the Environmental Protection Agency and with previous results. Special samples collected during the period of fallout from Japan had measurable Iodine-131 and Cesium-137, consistent with results reported by EPA in the western United States.

Milk

Liquid

Iodine-131, other gamma-emitting radionuclides

Thirty-four samples, including two duplicates, were collected.  Iodine-131 was reported near the detection level in one weekly sample during the period of fallout from Fukushima. The reported value was 0.1 percent of the Food and Drug Administration’s Limit for Public Health. 

Large Game Animals

Tissue

Gamma-emitting radionuclides

One elk sampled. Cesium-137 was detected in muscle tissue of at a level within background concentrations. Iodine-131 was not detected in the thyroid.