Q4 2018 Report

INL Site

Agricultural Product, Wildlife, and Soil 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 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 third or 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 wildlife samples available during the fourth quarter of 2018.

Milk Sampling

Milk samples were collected weekly at Idaho Falls and Terreton. Monthly samples were collected at five other locations around the INL Site (Figure 12) during the fourth 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 131I.  Semi-annual samples were collected and analyzed for 90Sr and tritium during the fourth quarter.

Neither 131I nor 137Cs was detected in any weekly or monthly samples during the fourth 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-7.

Figure 13

Results for 90Sr and tritium are listed in Appendix C, Table C-8. Strontium-90 was not detected in any of the samples analyzed this quarter.

Tritium was detected in one of seven samples analyzed, with a value of 88 pCi/L in the sample from Dietrich at a concentration similar to those previously measured and 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).

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Large Game Animal Sampling

No large game animals were sampled during the fourth quarter.

Waterfowl

Waterfowl are collected each year by the ESER contractor at a wastewater pond on the INL Site and at a location off the INL Site. Four waterfowl were collected from a pond located at the Advanced Test Reactor (ATR) Complex. Two control waterfowl were collected from the Market Lake area near Roberts. Each sample was divided into the following three sub-samples: 1) edible tissue (muscle, gizzard, heart, and liver), 2) external portion (feathers, feet, and head), and 3) all remaining tissue. All samples were analyzed for gamma-emitting radionuclides, 90Sr, and actinides (americium-241 [241Am], plutonium-238 [238Pu], and plutonium-239/240 [239/240Pu]). These radionuclides were selected because they have historically been measured in liquid effluents from some INL Site facilities.

A total of four human-made radionuclides were detected in edible, exterior, and remainder sub-samples from ducks collected at the ATR Complex ponds (Table 1). These were cobalt-60 (60Co), zinc-65 (65Zn), 90Sr, and 137Cs. Of these four nuclides, all but 90Sr were found in the edible tissues (Appendix C, Table C-9). No human-made radionuclides were detected in either of the control ducks.

The maximum potential dose from eating 225 g (8 oz) of duck meat collected in 2018 was calculated. Doses from consuming waterfowl are conservatively based on the assumption that ducks are eaten immediately after leaving the pond and no radioactive decay occurs. The maximum potential dose of 0.016 mrem from these waterfowl samples is much lower than the doses estimated for 2015 (0.49 mrem) and somewhat lower than those in 2017 (0.046 mrem). The Hypalon™ liner was replaced in the west disposal pond in 2016 and associated debris was removed with the liner and is no longer available to waterfowl.

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Radiation in Our World

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

Radiation Exposure and Dose

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