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 2002. 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 samples were collected weekly in Idaho Falls and monthly at nine
other locations around the INEEL (Figure 11) during the third quarter of
2002. All samples were analyzed for gamma emitting radionuclides.
Samples are analyzed for 90Sr during the second and fourth
Data for 131I and 137Cs in milk samples are listed in Table C-7. Iodine-131 or 137Cs were not measured above the 2s value in any milk sample during this quarter.
Seven lettuce samples were collected from private gardens and analyzed for gamma emitting radionuclides and 90Sr. No man-made gamma emitting radionuclides were detected in any of the samples. Strontium-90 was measured in five samples, those from Arco, Carey, Howe, Monteview, and Mud Lake above their 2s values. The highest concentration of 90Sr was measured in the sample from Carey at 283.0 ± 160.0 pCi/kg (dry) (10.5 ± 5.93 Bq/kg [dry]).
A total of 15 wheat samples were collected from local grain elevators. All samples were analyzed for gamma-emitting radionuclides and 90Sr. Cesium-137 was measured above the 2s value in the sample from Aberdeen. Strontium-90 was measured above the 2s value in the sample from Monteview. Data for 137Cs and 90Sr in all wheat samples taken during the third quarter are listed in Appendix C, Table C-8 and Table C-9.
Large Game Animal Sampling
Four game animals were sampled during the third quarter of 2002. All were killed as a result of vehicular collisions. These accidents involved three mule deer (Odocoileus hemionus) and one 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 tissue and measured in the muscle tissue and thyroid from a single mule deer sampled on August 8, 2002.
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, 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 third quarter of 2002, three marmots were collected from the Subsurface Disposal Area (SDA) of the RWMC. Two marmots were also collected, as controls, from the Pocatello Zoo. 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. Four samples of the edible portion of the marmot had results greater than their associated 2s for at least one radionuclide. Two samples from the SDA had 137Cs above the 2s, one of these samples also had detectable 90Sr. Two control samples exceeded their 2s values, one for ruthenium-103 and one for 90Sr. These four samples, plus one additional sample also exceeded their 2s values for certain radionuclides in their viscera and remainder samples (Table 2 below). Results for all marmot samples are listed in Table C-11, Appendix C.
The potential dose from eating the most contaminated edible portions of the marmots collected in 2002 is .0073 mrem. Well below the EPA limit of 10 mrem.
Table 2. Radionuclides detected in 2002 marmot samples