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Lichen Radionuclide Baseline Research

This research overview delves into the importance of studying radiation in Alaska, focusing on past and current research, definitions of radionuclide units, and the impact of nuclear contamination in the Arctic region. The study includes detailed information on nuclear power plants and underground tests in Alaska, previous research findings, sampling methodology, lichen and soil analysis, data interpretation using a Gamma Counter, and future research objectives.

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Lichen Radionuclide Baseline Research

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  1. Lichen Radionuclide Baseline Research By Loda Griffeth

  2. Overview • Definitions • Importance • Background: Radiation in Alaska • Past Research • Current Research

  3. Definitions Units • Becquerel (Bq) = 1 Disintegrations/sec (dps) • Curie (Ci) =3.7 X 1010 dps • Gray (Gy) = 1 Joule/kg of material • Sievert (Sv) = 1 Gy*Quality Factor (Q) • Megaton (MT) = 4.18 X 1015 Joules

  4. Importance • Arctic is a sink for radioactive contamination • Effect on subsistence lifestyles • Major source – nuclear weapons testing (1960’s) • Other sources – nuclear power plants and Chernobyl fallout.

  5. Radiation in Alaska • Bilibino Nuclear Power Plant • Fort Greely Nuclear Power Plant • Amchitka – Underground Nuclear Tests

  6. Bilibino Nuclear Power Plant • Chukotka, Russia • Above Arctic Circle • 4 - Light water graphite-12MW (LWGR-12) • Built 1974 (30 yrs) • No containment structure • Shutdown 2006-2010 Source: www.rosatom.com/english/stations/bilibino/bil_1.htm

  7. Bilibino Nuclear Power Plant Fairbanks: 2012-km and Nome: 1304-km

  8. Ft. Greely Nuclear Power Plant • Near Delta Junction • Operated 1962-1971 • 1.5-MW Stationary Medium Power (SM-1A) • 1997 leakage detected • Clean-up and decommissioning is on-going

  9. Project Year Est. Yield Depth (m) Purpose Longshot 1965 80kt 716 Seismic Testing Milrow 1969 ~1 Mt 1220 Seismic Calibration Cannikin 1971 ~ 5 Mt 1790 Device Testing Amchitka Island • Summary of the three nuclear test conducted on the island. • Hydrological study • Sampling • Long term monitoring

  10. Previous Research Research conducted in 1987, a year after the Chernobyl accident: Sampling Locations • Barrow (71N, 156W) • Colville River (70N, 151W) • Anaktuvuk Pass (68N, 151W) • Nome (64N, 165W) • Fairbanks (64N, 147W)

  11. Vegetation Moss Lichen Mushrooms Lake Sediment Soil Subsistence Foods White Fish Caribou Bowhead Whale Previous Research Sampling Materials

  12. Previous Research Results from a radiocesium study conducted in 1987 • Cs-137 levels were low in all samples • Deposition of Cs-137 varied by a factor of 28+ • Cs-137 was greater in samples collected in Fairbanks • Cs-137 levels were generally lower in soils than lichen

  13. Previous Research Transport via Western Canada:

  14. Current Research • Objectives • Sampling Methodology • Gamma Counter • Data • Results • Future Research

  15. Objectives • Establish composition and spatial distribution radionuclides in Alaska • Assess known and potential lichen indicator species • Derive correlation between baseline lichen data and radiological data • Derive correlation between current baseline lichen data and potential bioconcentration effects in caribou

  16. Methodology - Lichen • Separate lichen from other natural materials, store in sealed, tared plastic bags. • Sample area – 1/4-meter (smaller, if lichen abundance is low). • Drying time – 24-hours at 100°C. • Ash for 24-hours at 450°C and store in tared plastic bags. Upper Right: Lichen abundance at Moose Pass. Lower Right: Sampling area at Moose Pass containing Cadina stellaris.

  17. Methodology - Soil • Metal corer 5x10-cm • Split 8-10-cm plugs into 1-5-cm and 6-10-cm plugs • Obtained replicate samples from lichen plots & 1-2 additional samples per site. • Dried and ashed samples • Sifted samples – discarded particles >2-mm size Upper Right: Soil sampling using a metal corer at Moose Pass along the Seward Highway. Lower Right: Soil sample collected at Moose Pass along the Seward Highway.

  18. * Indicates one of several types of lichen collected from site. Sampling Sites

  19. Data • Lichen Samples (30) • Soil Samples (46) • 35% Analyzed • Replicate measurements to ensure precision • Multiple vials to ensure homogeneity

  20. Gamma Counter Canberra Germanium Detector:

  21. Gamma Counter Genie 2000 Spectroscopy and Analysis Software:

  22. Cosmogenic Nuclide Be-7 Fission Product Cs-137 U-235?? Primordial Nuclides K-40 Decay Series Decay Series Bi-214 Pb-214 Pa-234M Ra-226 Results

  23. Results

  24. Results

  25. Results

  26. Results • Cs-137 – Good Model • Activity increases with Latitude • Higher activity in lichen than activity in soil samples • Low activity in Seward Hwy (SH) and Denali highway (DH) samples • U-235 – Good to Marginal Model • Activity increases with latitude and longitude • Bethel samples have high activity • Low activity in Seward Hwy and Denali Hwy samples • Higher activity in lichen than activity in soil samples

  27. Future Research • Establish composition and spatial distribution radionuclides in Alaska • Assess known and potential lichen indicator species • Derive correlation between baseline lichen data and radiological data • Derive correlation between current baseline lichen data and potential bioconcentration effects in caribou

  28. Acknowledgements • John Kelley (IMS) • Larry Duffy • Adrienne Orr • Stan Read and Doug Dasher (ADEC) • Richard Stolzberg • Chemistry Department • Pacific Northwest National Laboratories • Laodong Guo and Celine Gueguen (IARC)

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