Nick Beresford & David Copplestone Centre for Ecology & Hydrology - Lancaster 1 st – 3 rd April 2014

 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

 Available at no cost for download on-line  Comparatively well documented  Being maintained and upgraded  Training available

BDAC Series of paper in: Woodhead, D.S. (Ed.), Protection of the environment from ionising radiation. Journal of Environmental Radioactivity, 66.

 Tiers are Levels  CRs are Bivs  EMCLs are BCGs (Biota Concentration Guides)  DCCs are DCFs (Dose Conversion Factor)

RESRAD-BIOTA Level

Based 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

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 95th percentile CR values predicted using a kinetic-allometric approach

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)

 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

RadionuclideFreshwater (Bq/l) H-34 Co Cs Pu RadionuclideSoil (Bq/kg) Cs Am Pu Co Sr-901.3

 Site specific CR values available for aquatic animal:  Co 1500; Cs 9000; H 0.25; Pu RadionuclideFreshwater (Bq/l) H-34 Co Cs Pu

 Also uses CRs (or Bivs), but:

 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

 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 = aM b where a and b are constants

 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:

 For (some) radionuclides both the biological half-life (often M 0.25 ) and transfer from diet (M ) 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

kg/d T1/2 =13.22*(mass )

kg/d T1/2 =13.22*(mass ) Ff=8.89*(mass ) Transfer coefficient F f ( d kg -1 ) = Equilibrium activity concentration in animal (Bq kg -1 FW) Daily intake of radionuclide (Bq d -1 )

kg/d T1/2 =13.22*(mass ) Ff=8.89*(mass ) DMI=0.0551*(mass 0.74 )

kg/d T1/2 =13.22*(mass ) Ff=8.89*(mass ) DMI=0.0551*(mass 0.74 )

kg/d T1/2 =13.22*(mass ) Ff=8.89*(mass ) DMI=0.0551*(mass 0.74 ) Bq/kg = Ff x DMI Transfer coefficient F f ( 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 Bq/kg Pu Bq/kg  Water concentration: Cs 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

RESRAD-BIOTA Level 3 Diet – 70 % seeds and 30 % invertebrates Concentration ratios for dormouse diet Seed Cs Pu-239 5E-3 Invertebrate Cs Pu