Fourth Quarter 2004
INEEL Quarterly Site Environmental Report
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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 fourth 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, potatoes, large game animals, and waterfowl sampled during the fourth quarter of 2004. 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
12) during the fourth quarter of 2004. All samples were analyzed for gamma
emitting radionuclides. Samples are analyzed for 90Sr during the
second and fourth quarters.
Data for weekly and monthly 131I and 137Cs measurements in milk samples are listed in Table C-8. No 131I was detected (measured above the 3s value) in any milk sample during the fourth quarter. Neither 131I nor 137Cs was detected in any weekly or monthly milk sample.
Bi-annual 90Sr and tritium concentrations measured in milk are reported in Table C-9. Two of four milk samples, collected at Dietrich and Roberts, had detectable concentrations of 90Sr. The maximum 90Sr result was (1.17 ± 0.18) pCi/L ([0.043 ± 0.007] Bq/L). This result is below the DCG for 90Sr in drinking water of 100 pCi/L and within the range of historical results measured at the INEEL and background measurements made by EPA during the past 10 years in Region 10.
Tritium was detected in four of the five biannual milk samples. The
maximum result, (107.00 ± 26.50) pCi/L ([3.96 ± 0.98] Bq/L), is below the
DCG for tritium in drinking water of 2 x 106 pCi/L and within
historical measurements at the INEEL and background measurements made by EPA
during 1995-2005 in Region 10.
Figure 12. ESER Program milk sampling locations.
Eleven potato samples were collected from area growers and from out-of-state locations. All samples were analyzed for gamma emitting radionuclides and 90Sr. No 137Cs was measured in any sample. Strontium-90 was detected in two of the samples above their respective 3s values. The maximum concentration of 90Sr was from a duplicate sample collected from Taber at (274 ± 75) pCi/kg (dry) (approximately [10 ± 3] Bq/kg). Strontium-90 was not detected in the other duplicate sample. This value is within historic concentrations measured in potatoes collected from farms surrounding the INEEL.
Data for 137Cs and 90Sr
in all potato samples taken during the fourth quarter are listed in
Table C -10 (Appendix C).
Five game animals were sampled during the fourth quarter of 2004. Four were killed as a result of vehicular collisions on INEEL roads. The accidents involved two pronghorn antelope and two elk. Samples were also collected from a whitetail deer killed in Montana by a hunter. 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 11.
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 and 131I were not detected in any of the tissue of any animal.
Six waterfowl were collected during 2004: Four Coots from the control location of Market Lake and two from the Test Reactor Area (TRA) sewage treatment lagoon. All were analyzed for gamma emitting radionuclides with a subset analyzed for 90Sr, 238Pu, 239/240Pu, and 241Am. Concentrations of radionuclides measured in edible tissues are shown in Table C-12.
Cesium-137 was detected at concentrations greater than the 3s value in the muscle tissue of the two Coots collected from TRA. The maximum concentration was (0.20 ± 0.02) pCi/g ([733 ± 81 Bq/g]). No other radionuclides were measured above the 3s concentration in any edible tissue.
Waterfowl hunting is not allowed on the INEEL,
but a maximum potential exposure scenario to humans would be someone collecting
a contaminated duck and immediately consuming all muscle, liver, heart, and
gizzard tissue (average 225 g). The maximum potential dose from eating 225 g (8
oz) of meat from the most contaminated waterfowl collected in 2004 was estimated
to be 0.002 mrem (0.2 mSv). This dose is approximately equal to that estimated
last year and orders of magnitude lower than the estimated dose of 0.89 mrem
calculated in 2002. This is attributed primarily to the fact that the TRA Warm
Waste Pond, containing low levels of radionuclides, is no longer in operation.
This dose is far less than 363 mrem we receive each year from ambient sources
and the 100 mrem per year DOE regulatory dose limit.
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