Transfer to biota

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Transfer to biota
Centre for Ecology and Hydrology - NERC
For the ERICA project
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Aim

• To quantify the transfer of radionuclides from
  media
• (air or soil or water) to the whole body of
  animals and plants
• Table of content
• Concentration Ratios
• Terrestrial CR values
• Terrestrial S,H,C and P isotopes
• Aquatic CR values
• Sources of CR values

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Concentration Ratios

• CR concentration in animal or plant (Bq/kg fw)
• concentration in media (Bq/kg or
  Bq/l)
• For all radionuclides EXCEPT C, H, S and P
  isotopes

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Terrestrial CR values

• Concentration in CR x concentration
• animal or plant in soil
• (Bq/kg (Bq/kg
• fresh weight) dry
  weight)

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Terrestrial S,H,C and P isotopes

• Concentration in biota calculated from air
  concentrations using a specific activity approach

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Aquatic CR values

• Concentration in CR x concentration
• animal or plant in water
• (Bq/kg fresh weight) (Bq/l)
• If concentration in water not available
• Concentration in water conc. in sediment
• Kd

Kd conc. in sediment conc. in water
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Sources of CR values

• Extensive review of literature carried out in
  ERICA.
• Where available a best estimate CR value
  (meanSD) has been estimated from the compiled
  databases.
• If specific radioecological data are not
  available, then a number of approaches have been
  used to derive CR values including
• Stable isotope data
• allometric relationships, or other modelling
  approaches
• assume the same CR value as for an element with a
  similar biogeochemistry (e.g. Pu for Am)
• assume the same CR value as for the relevant
  radionuclide and a similar reference organism
  (e.g. mammal for bird).
• As a last resort
• for terrestrial - use a CR value of 1 or the
  highest available CR if values gt1 are available
  for any reference organism
• for aquatic - justify using a value for an
  appropriate reference organism in a different
  aquatic ecosystem (e.g. assume marine fish value
  for freshwater fish) if available if not - use
  highest available CR value for the aquatic
  ecosystem.