Page History

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Technical issues related to the ERICA Tool (on Facilia website)

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Posted: Asked during training course 24-26th November 2011

OBT?

From:
Franck Jourdain
CEA
France

Question:
How would you assess OBT releases using the ERICA Tool?

Answer:
None of the radiological environmental assessment tools that we are aware of are parameterised for OBT. Obviously OBT activity concentrations in biota could be input into the ERICA Tool (Tier 2 or 3) if available and dose rates estimated. If measured biota activity concentrations are lacking then, for aquatic ecosystems, you would need appropriate CR values for OBT; these could be used to replace the default CR values in Tiers 2 or 3. For terrestrial ecosystems it may be a little more complicated if you have measured/modelled OBT concentrations in soil since the CR values relate wholebody activity concentrations to those in air. You could use the Tool to give you the absorbed dose rate assuming 1 Bq/kg in the organisms of interest. If you had appropriate CR values you could then estimate the internal dose rate as: media activity concentration x CR x absorbed dose rate per Bq/kg. External dose rates from H-3 can be assumed to be zero.

The DCC values within the ERICA Tool (or RESRAD-BIOTA) can be used to generate unweighted internal dose rates for H-3 regardless of if present as HTO or OBT. The user can then define their own radiation weighting factor for low energy beta emitters (such as H-3). Note some dose coefficients for human assessment (effective dose coefficients) relate weighted absorbed dose rates to the activity ingested or inhaled and consequently these are higher for OBT than HTO as a consequence of the longer retention time of OBT compared to HTO. However, the DCC in the ERIA Tool relate absorbed dose rate to the whole organisms activity concentration and consequently under the simplified assumption of homeogenous distribution would be the same for HTO and OBT.

The underlying methodology used to estimate the CR values for terrestrial organisms in the ERICA Tool accounts for OBT and HTO intakes; the equations, presented in Galeriu et al. 2003, could be used to derive OBT CR values.

Galeriu D, Beresford, N.A., Melintescu, A., Avila, R. and Crout, N.M.J. 2003. Predicting tritium and radiocarbon in wild animals Contributed Papers Conf. on the Protection of the Environment from the Effects of Ionizing Radiation (Stockholm, 2003) (Vienna: IAEA) pp 186-9 (IAEA-CN-109).

Answered 29/11/2010

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Posted: Asked during training course 24-26th November 2011

Chemical risk assessment?

From:
Maria Psaltaki
National Technical University of Athens
Greece

Question:
Are there models similar to the ERICA Tool available for chemical risk assessment?

Answer:
Those we are aware of are the SADA package, RESRAD-ECORISK and RESRAD-Chem. All are freely available although we note the RESRAD website states that RESRAD-Chem and RESRAD-ECORISK are no-longer being updated.

Answered 29/11/2010

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Posted: Asked during training course 24-26th November 2011

Assessment of estuarine ecosystem?

From:
Sarah Hunak
AMEC
UK

Question:

How would I conduct an assessment of an estuarine ecosystem using the ERICA Tool?

Answer:
The ERICA Tool is not parameterised to consider estuarine ecosystems. However, the IAEA handbook on radionuclide transfer to wildlife will provide summary tables for estuarine ecosystems as will the on-line wildlife transfer database. Data will be more limited than for other ecosystems and will initially originate largely (perhaps only) from studies of the Baltic Sea and a number of Japanese estuaries. The issue of Radiation Environmental Biophysics containing papers associated with the wildlife transfer database has a paper on transfer to estuarine wildlife by Takata et al.; the same authors have also recently published estuarine kd values.

If you do not have CR or kd values specifically for estuarine ecosystems then we suggest selecting the value which will result in the most conservative assessment from either the marine or freshwater ecosystem.

Answered 29/11/2010

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Posted: 18/11/2010

Non-human biota, environment or wildlife?

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