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AGRICULTURAL PRODUCTS AND WILDLIFE SAMPLING

Another potential pathway for contaminants to reach humans is through the food chain. The ESER Program samples multiple agricultural products and game animals from around the INEEL and Southeast Idaho. Specifically, milk, wheat, potatoes, garden lettuce, sheep, big game, waterfowl, doves, and marmots are sampled. Milk is sampled throughout the year. Sheep are sampled during the second quarter. Lettuce and wheat are sampled during the third quarter, while potatoes and waterfowl are collected during the fourth quarter. See Table A-1, Appendix A, for more details on agricultural product and wildlife sampling. This section discusses results from milk, lettuce, wheat, and large game sampled during the third quarter of 2003. A summary of approximate minimum detectable concentrations (MDCs) for radiological analyses is provided in Appendix B. There are no regulatory standards for radionuclide concentrations in agricultural products or wildlife tissues.

MILK SAMPLING

LETTUCE SAMPLING

In 2003 the ESER Program tested two prototype self-contained lettuce planters at the sampling locations in Atomic City and at the EFS on the INEEL. These locations were relatively remote and had no access to water, requiring that a self-watering system be developed. This prototype method allows for the placement and collection of lettuce at areas previously unavailable to the public (i.e., on the INEEL). The planters 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.

Eight lettuce samples and one duplicate were collected from private gardens and the prototype planters. Each sample was analyzed for gamma emitting radionuclides and ⁹⁰Sr. The only man-made gamma emitting radionuclide detected in any of the samples was ¹³⁷Cs in the sample from Idaho Falls with a maximum concentration of 1.1 ± 0.3 pCi/g. Strontium-90 was measured in one sample collected from the EFS. The highest concentration of ⁹⁰Sr was measured in the sample from EFS sample at 4.4 ± 1.3 pCi/g (dry) (0.1 ± 0.06 Bq/g [dry]).

Data for ¹³⁷Cs and ⁹⁰Sr in all lettuce samples taken during the third quarter listed in Table C-8 (Appendix C).

WHEAT SAMPLING

A total of 12 wheat samples were collected from local grain elevators. All samples were analyzed for gamma-emitting radionuclides and ⁹⁰Sr. No man-made radionuclides were positively detected in wheat samples above their 3s levels during 2003. Data for ¹³⁷Cs and ⁹⁰Sr in all wheat samples taken during the third quarter are listed in Appendix C, Table C-9.

LARGE GAME ANIMAL SAMPLING

Six game animals were sampled during the third quarter of 2003. All were killed as a result of vehicular collisions. These accidents all involved pronghorn antelope (Antilocapra americana). Efforts were made to collect samples of thyroid, liver, and muscle tissue from each animal, but due to their condition at the time of sampling not all animals provided all samples. Cesium-137 and ¹³¹I data for all big game samples are listed in Appendix C, Table C-10.

Each sample collected was analyzed for gamma emitting radionuclides. Liver and muscle tissue of all animals had detectable concentrations of naturally occurring potassium-40. Cesium-137 was detected in the liver and muscle tissue from an antelope sampled on September 25, 2003. Iodine-131 was also questionably detected in the muscle tissue of this animal.

The concentrations measured in the above samples are within the range of values for samples collected in the past. Likewise, the presence of ¹³⁷Cs is commonly associated with fallout from past weapons testing and nuclear accidents (i.e., Chernobyl).

MARMOTS

Marmots, otherwise known as rockchucks, are a large member of the squirrel family and are hunted and consumed by the Native American people in the area. A population of yellow-bellied marmots exists around and within the boundaries of the Radioactive Waste Management Complex (RWMC). During the second and third quarters of 2003, three marmots were collected from the Subsurface Disposal Area (SDA) of the RWMC. Two marmots were also collected as controls from the Pocatello Zoo and Tie Canyon near Blackfoot. Each marmot was dissected into three samples, the edible portion (muscle tissue), viscera, and the remainder (skin, fur, bones). All samples were analyzed for gamma-emitting radionuclides, ⁹⁰Sr, ²³⁸Pu, ^239/240Pu, and ²⁴¹Am. Five samples of the edible portion of the marmot had results greater than their associated 3s for at least one radionuclide. One sample from the SDA had ²⁴¹Am above the 3s, while one sample from Tie Canyon had ¹³⁷Cs above the 2s.

Two samples, also from the SDA had detectable (above the 3s) ¹³⁷Cs. All samples had detectable ⁹⁰Sr in their edible tissue. These five samples, plus one additional sample also exceeded their 3s values for certain radionuclides in their viscera and remainder samples (Table 2). Results for all marmot samples are listed in Table C-11, Appendix C.

The potential dose from eating 225 g of the most contaminated edible portions of the marmots collected in 2003 is 0.006 mrem (0.06 μSv), which is well below the EPA limit of 10 mrem.

 

Table 2.   Radionuclides detected in 2002 marmot samples.

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