RESRADBIOTA Nick Beresford David Copplestone Centre for Ecology
RESRAD-BIOTA Nick Beresford & David Copplestone Centre for Ecology & Hydrology - Lancaster 27 th – 29 th June 2012
RESRAD-BIOTA ¥ Code which implements the USDOE’s Graded approach (replaces BCG-calculator) ¥ Part of the RESRAD suite of models ¥ Freshwater and terrestrial ecosystems ¥ Database contains 46 radionuclides ¥ Four organisms – terrestrial animal, terrestrial plant, riparian animal and aquatic animal ¥ Can create organisms & simple foodchains www. ceh. ac. uk/PROTECT
Availability and documentation ¥ Available at no cost for download on-line ¥ Comparatively well documented ¥ Being maintained and upgraded ¥ Training available
RESRAD-BIOTA www. ead. anl. gov/resrad/home 2/
USDOE Graded Approach Series of paper in: Woodhead, D. S. (Ed. ), 2003. Protection of the environment from ionising radiation. Journal of Environmental Radioactivity, 66. BDAC
RESRAD-BIOTA v’s ERICA Terms used ¥ Tiers are Levels ¥ CRs are Bivs ¥ EMCLs are BCGs (Biota Concentration Guides) ¥ DCCs are DCFs (Dose Conversion Factor) www. ceh. ac. uk/PROTECT
RESRAD-BIOTA Level www. ceh. ac. uk/PROTECT
USDOE - benchmarks Based on NCRP & IAEA set dose limits for protection of: Aquatic animals - 10 m. Gy d-1 Terrestrial plants - 10 m. Gy d-1 Terrestrial animals - 1 m. Gy d-1
RESRAD-BIOTA - BCGs Estimated assuming: ¥ Infinitely large (internal) and small (external) geometries for dose calculations ¥ Daughter T 1/2’s up to 100 y included ¥ All terrestrial organisms 100% in soil; aquatic 100% water-sediment interface ¥ ‘Maximum’ CR values or 95 th percentile CR values predicted using a kineticallometric approach
LEVEL 1
Screening assessment - Levels 1 ¥ Cs-137 ¥ Am-241 ¥ Cf-252 ¥ Use water 10 Bq/l sediment 1000 Bq/kg water 1 Bq/kg 10 µGy/h screening level (2. 4 E-4 Gy/d)
Level 1 ¥ Run the freshwater and terrestrial scenarios from the ERICA Tier 1 practical Use ERICA screening value 10 µGy/h ¥ Leave out the radionuclides which are not included in RESRAD ¥ www. ceh. ac. uk/PROTECT
Radionuclide H-3 Co-60 Cs-137 Pu-239 Freshwater (Bq/l) 4 0. 3 0. 04 www. ceh. ac. uk/PROTECT Radionuclide Cs-137 Am-241 Pu-239 Co-60 Sr-90 Soil (Bq/kg) 10 0. 3 170 0. 1 1. 3
Level 2
Level 2 Radionuclide H-3 Co-60 Cs-137 Pu-239 Freshwater (Bq/l) 4 0. 3 0. 04 ¥ Site specific CR values available for aquatic animal: ¥ Co 1500; Cs 9000; H 0. 25; Pu 200 www. ceh. ac. uk/PROTECT
Level 3
RESRAD-BIOTA ¥ Also uses CRs (or Bivs), but:
RESRAD-BIOTA ¥ Can use kinetic-allometric approach with simple foodchains for terrestrial/riparian vertebrates Root uptake Soil contamination Vegetation Soil invertebrate Herbivorous mammals Carnivorous mammals Fugitive dust Water contamination Herbivorous birds
What is Allometry? ¥ Size effects rates of all biological structures and processes from cellular metabolism to population dynamics ¥ The dependence of a biological variable Y on a body mass M is typically characterised by an allometric scaling law of the form: Y = a. Mb where a and b are constants
What is Allometry? ¥b most often = ‘quartile values’: ¥ metabolic rates scale as M 0. 75 ¥ M 0. 75 is often referred to as metabolic live -weight ¥ life-span scales as M 0. 25 ¥ food, water and inhalation rates scale as M 0. 75 ¥ All potential useful for radioecological models, but: www. ceh. ac. uk/PROTECT
Allometric – radioecological parameters ¥ For (some) radionuclides both the biological half-life (often M 0. 25) and transfer from diet (M-0. 75) have been found to scale allometrically ¥ RESRAD-BIOTA uses allometric relationships for radionuclide biological halflives and a number of other animal parameters (e. g. food & water intake, lifespan, inhalation rate) for terrestrial and riparian vertebrates www. ceh. ac. uk/PROTECT
Allometric calculations, e. g. Cs kg/d T 1/2 =13. 22*(mass 0. 237) www. ceh. ac. uk/PROTECT
Allometric calculations, Transfer coefficient Ff ( d kg-1 e. g. ) = Cs Equilibrium activity concentration in animal (Bq kg-1 FW) Daily intake of radionuclide (Bq d -1) kg/d T 1/2 =13. 22*(mass 0. 237) Ff=8. 89*(mass-0. 73)
Allometric calculations, e. g. Cs kg/d T 1/2 =13. 22*(mass 0. 237) Ff=8. 89*(mass-0. 73) DMI=0. 0551*(mass 0. 74)
Allometric calculations, e. g. Cs kg/d T 1/2 =13. 22*(mass 0. 237) Ff=8. 89*(mass-0. 73) DMI=0. 0551*(mass 0. 74)
-1) = Cs Allometric calculations, Transfer coefficient Ff ( d kge. g. Equilibrium activity concentration in animal (Bq kg-1 FW) Daily intake of radionuclide (Bq d -1) kg/d T 1/2 =13. 22*(mass 0. 237) Ff=8. 89*(mass-0. 73) Bq/kg = Ff x DMI=0. 0551*(mass 0. 74)
Create an organism and foodchain
RESRAD-BIOTA Level 3 ¥ Soil activity concentrations are available: Cs-137 1000 Bq/kg Pu-239 550 Bq/kg ¥ Water concentration: Cs-137 1 Bq/kg Pu-239 1 E-3 Bq/kg ¥ ¥ Alpha RBE=10; Cut-off half-life=180 Dormouse characteristics: Size – 9 x 3 x 3 cm Weight - 30 g Occupancy – 50% in soil/50% on soil
RESRAD-BIOTA Level 3 Diet – 70 % seeds and 30 % invertebrates Concentration ratios for dormouse diet Seed Cs-137 0. 7 Pu-239 5 E-3 Invertebrate Cs-137 0. 13 Pu-239 0. 1
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