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Nick Beresford & David Copplestone
RESRAD-BIOTA
Centre for Ecology & Hydrology - Lancaster 1st – 3rd April 2014
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.radioecology-exchange.org
Availability and documentation
Available at no cost for download on-line Comparatively well documented Being maintained and upgraded Training available
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RESRAD-BIOTA
www.ead.anl.gov/resrad/home2/
USDOE Graded Approach
BDAC
Series of paper in: Woodhead, D.S. (Ed.), 2003. Protection of the environment from ionising radiation. Journal of Environmental Radioactivity, 66.
RESRAD-BIOTA v’s ERICATerms used
Tiers are Levels CRs are Bivs EMCLs are BCGs (Biota Concentration
Guides) DCCs are DCFs (Dose Conversion Factor)
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www.ceh.ac.uk/PROTECT
RESRAD-BIOTA Level
USDOE - benchmarksBased on NCRP & IAEA set dose limits for protection of:
Aquatic animals - 10 mGy d-1
Terrestrial plants - 10 mGy d-1
Terrestrial animals - 1 mGy d-1
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RESRAD-BIOTA - BCGs
Estimated assuming: Infinitely large (internal) and small (external)
geometries for dose calculations Daughter T1/2’s up to 100 y included All terrestrial organisms 100% in soil; aquatic
100% water-sediment interface ‘Maximum’ CR values or 95th percentile CR
values predicted using a kinetic-allometric approach
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LEVEL 1
Screening assessment - Levels 1
Cs-137 water 10 Bq/l sediment 1000 Bq/kg
Am-241 sediment 1000 Bq/kg
Cf-252 water 1 Bq/kg
Use 10 µGy/h screening level (2.4E-4 Gy/d)
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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
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Radionuclide Freshwater (Bq/l)H-3 4Co-60 0.3Cs-137 0.3Pu-239 0.04
Radionuclide Soil (Bq/kg)Cs-137 10Am-241 0.3Pu-239 170Co-60 0.1Sr-90 1.3
Level 2
Level 2
Site specific CR values available for aquatic animal: Co 1500; Cs 9000; H 0.25; Pu 200
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Radionuclide Freshwater (Bq/l)H-3 4Co-60 0.3Cs-137 0.3Pu-239 0.04
Level 3
RESRAD-BIOTA
Also uses CRs (or Bivs), but:
RESRAD-BIOTA Can use kinetic-allometric approach with simple
foodchains for terrestrial/riparian vertebrates
Soil contamination
Fugitive dust
Vegetation
Soil invertebrate
Herbivorous mammals
Herbivorous birds
Carnivorous mammals
Water
contamination
Root uptake
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 = aMb
where a and b are constants
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What is Allometry?
b most often = ‘quartile values’:
metabolic rates scale as M0.75
M0.75 is often referred to as metabolic live-weight
life-span scales as M0.25 food, water and inhalation rates scale as M0.75
All potential useful for radioecological models, but:www.radioecology-exchange.org
Allometric – radioecological parameters
For (some) radionuclides both the biological half-life (often M0.25) and transfer from diet (M-
0.75) have been found to scale allometrically RESRAD-BIOTA uses allometric relationships
for radionuclide biological half-lives and a number of other animal parameters (e.g. food & water intake, life-span, inhalation rate) for terrestrial and riparian vertebrates
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Allometric calculations, e.g. Cs
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kg/d
T1/2 =13.22*(mass0.237)
Allometric calculations, e.g. Cs
kg/d
T1/2 =13.22*(mass0.237)
Ff=8.89*(mass-0.73)
Transfer coefficient Ff ( d kg-1) = Equilibrium activity concentration in animal (Bq kg-1 FW)
Daily intake of radionuclide (Bq d-1)
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Allometric calculations, e.g. Cs
kg/d
T1/2 =13.22*(mass0.237)
Ff=8.89*(mass-0.73)
DMI=0.0551*(mass0.74)
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Allometric calculations, e.g. Cs
kg/d
T1/2 =13.22*(mass0.237)
Ff=8.89*(mass-0.73)
DMI=0.0551*(mass0.74)
Allometric calculations, e.g. Cs
kg/d
T1/2 =13.22*(mass0.237)
Ff=8.89*(mass-0.73)
DMI=0.0551*(mass0.74)
Bq/kg = Ff x DMI
Transfer coefficient Ff ( d kg-1) = Equilibrium activity concentration in animal (Bq kg-1 FW)
Daily intake of radionuclide (Bq d-1)
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 1E-3 Bq/kg Alpha RBE=10; Cut-off half-life=180 Dormouse characteristics:
Size – 9x3x3 cm
Weight - 30 g
Occupancy – 50% in soil/50% on soil
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RESRAD-BIOTA Level 3
Diet – 70 % seeds and 30 % invertebrates
Concentration ratios for dormouse dietSeed
Cs-137 0.7
Pu-239 5E-3
Invertebrate
Cs-137 0.13
Pu-239 0.1
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