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 INL Site and Southeast Idaho. Specifically, milk, alfalfa, grain, potatoes, lettuce, large game animals, and waterfowl are sampled. Milk is sampled throughout the year and large game animals are sampled whenever large game animals are killed onsite from vehicle collisions. Alfalfa is collected during the second quarter, lettuce and grain are sampled during the third quarter, while potatoes are collected during the fourth quarter. Waterfowl are collected in either the third or fourth quarter. See Table A-1, Appendix A, for more details on agricultural product and wildlife sampling. This section discusses results from milk and alfalfa samples available during the second quarter of 2018.
Milk samples were collected weekly at Idaho Falls and Terreton. Monthly samples were collected at five other locations around the INL Site (Figure 13) during the second quarter of 2018. In addition to the local locations, commercially-available organic milk (from Colorado) was purchased as a control sample each month. All samples were analyzed for gamma emitting radionuclides, with particular emphasis on Iodine-131. Semi-annual samples were collected and analyzed for 90Sr and tritium.
Figure 13. ESER agriculture product sampling locations. Milk is collected at locations identified by blue circles.
Neither 131I nor 137Cs was detected in any weekly or monthly samples during the second quarter. No other human-made gamma-emitting radionuclides were found either. Data for 131I and 137Cs in milk samples are listed in Appendix C, Table C-6.
Results for 90Sr and tritium are listed in Appendix C, Table C-9. Strontium-90 was detected in three of seven samples analyzed. The maximum concentration of 0.21 pCi/L from Blackfoot is in the lower portion of the range for these values over the past several years. The presence of 90Sr at similar levels in samples from near the INL Site and Distant from the INL Site (as well as the organic milk from Colorado), does not indicate an INL Site impact of the results. There is no DCS for 90Sr in milk; however, for comparison the results were well below the drinking water DCS of 1.1 x 103 pCi/L.
Tritium was also detected in five of seven samples analyzed, with a maximum value of 171 pCi/L in the sample from Minidoka. All results were similar to those previously measured and similar to those found in other liquid media like precipitation. There is no DCS for tritium in milk, but the results were well below the DCS for tritium in drinking water (1.9 x 106 pCi/L).
Four samples of alfalfa (including one duplicate) were obtained from growers in the Howe, Mud Lake, and Idaho Falls areas. All samples were analyzed for gamma-emitting radionuclides and three samples for 90Sr. Data for 137Cs and 90Sr in alfalfa samples are listed in Appendix C, Table C-10.
No human-made gamma-emitting radionuclides were found in any of the samples this year. Strontium-90 was detected at 135 pCi/kg in one sample collected at Idaho Falls. During the five years alfalfa has been collected, 90Sr concentrations have been in the 70-150 pCi/kg range.
Radiation has always been a part of the natural environment in the form of cosmic radiation, cosmogenic radionuclides [carbon-14 (14C), Beryllium-7 (7Be), and tritium (3H)], and naturally occurring radionuclides, such as potassium-40 (40K), and the thorium, uranium, and actinium series radionuclides which have very long half lives. Additionally, human-made radionuclides were distributed throughout the world beginning in the early 1940s. Atmospheric testing of nuclear weapons from 1945 through 1980 and nuclear power plant accidents, such as the Chernobyl accident in the former Soviet Union during 1986, have resulted in fallout of detectable radionuclides around the world. This natural and manmade global fallout radioactivity is referred to as background radiation. MORE
The primary concern regarding radioactivity is the amount of energy deposited by particles or gamma radiation to the surrounding environment. It is possible that the energy from radiation may damage living tissue. When radiation interacts with the atoms of a given substance, it can alter the number of electrons associated with those atoms (usually removing orbital electrons). This is called ionization. MORE