The INL Site is situated in a large agricultural area that produces many food products. The ESER Team monitors the following foods for potential migration and deposition of effluents from the INL. These foods were chosen for their abundance in the upper Snake River valley and their availability for testing.
Lettuce samples are obtained from private gardens in communities in the vicinity of the INL. Samples are washed to remove soil (as in normal food preparation), dried, reduced to a powdered form and weighed. All lettuce samples are analyzed for Strontium-90 and gamma-emitting radionuclides.
The collection of lettuce from home gardens around the INL typically depends on availability. To make this sampling more reliable, ESER added one prototype lettuce planter at the Experimental Field Station (EFS) and five lettuce planters off the INL Site at Atomic City, the FAA Tower, Howe, Idaho Falls and Monteview. These locations are relatively remote and have no access to water, requiring that a self-watering system be developed or are at locations where lettuce has not been obtainable during the sampling season. This method allows for the placement and collection of lettuce at areas previously unavailable to the public (i.e., on the INL Site). The boxes are set out in the spring with the lettuce grown from seed. This new method also allows for the accumulation of deposited radionuclides on the plant surface throughout the growth cycle.
Ingestion of milk is a primary pathway by which radioactive materials released into the atmosphere may reach the offsite population. Milk samples are collected at areas close to the INL Site boundary and distant to the INL Site. In addition to the local locations, commercially-available organic milk from Colorado was purchased as a control sample each month. Milk from each location is analyzed for Iodine-131 (131I), and one analysis for strontium-90 and tritium at each location is performed during the year.
Milk was the first agricultural product to be monitored, beginning in at least 1957. The number of samples collected per year has been relatively constant since about 1962, though locations change as dairies go out of business and are replaced by others. Because of improvements in counting technology, the detection limit for 131I has decreased from about 15,000 pCi/L in early sampling to the current detection level of about 0.5 pCi/L.
Potato samples are collected from storage warehouses in the INL Site vicinity. Control samples are also analyzed. The samples, with cleaned skins included, are processed and weighed. All potato samples are analyzed from Strontium-90 and gamma-emitting radionuclides.
Grain (wheat and barley) samples are collected from grain elevators in the region surrounding the INL Site. In addition, commercially-available samples are obtained from outside the local area. All wheat samples are analyzed for Strontium-90 and gamma-emitting radionuclides.
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