What to look for when interpreting an assessment

What to look for when interpreting an assessment Centre for Ecology & Hydrology – Lancaster 1 st – 3 rd April 2014

Objective ¥ Give an overview of what may impact on assessment results using the available approaches In part based on things we know are being done ¥ Consider chronology of development, misuse of default values, double accounting, screening tier application ¥ Not considering dispersion modelling and sampling strategies ¥ www. radioecology-exchange. org

Chronology ¥ Environmental Radiological assessment approaches have developed rapidly over the last 15 y ¥ A number of approaches have been made freely available Some of these have been superseded ¥ But they are still available & are being used ¥ www. radioecology-exchange. org

Chronology ¥ UK ¥ Environment Agency R&D 128 - 2001 Spreadsheet model for limited number of radionuclides ¥ Comparatively limited review to derive CR values ¥ Dosimetry methods similar to later approaches ¥ ¥ Environment Agency Sp 1 a – 2003 ¥ Supports R&D 128 including derivation of complete CR data sets using a ‘guidance approach’ (can be extremely conservative) www. radioecology-exchange. org

Chronology ¥ Europe ¥ FASSET (EC) 2001 -2004 Establish a framework for radiological environmental protection from source characterisation – interpretation, including: ¥ Tabulated CR and DCC values for: ¥ ¥ radionuclides of 20 elements circa 30 reference organism in 7 ecosystems Developed the on-line FASSET Radiation Effects Database www. radioecology-exchange. org

Chronology ¥ Europe ¥ EPIC (EC) 2000 -2003 Establish a framework for radiological environmental protection for the Arctic ¥ Ran concurrent to FASSET and shared CR database ¥ ¥ Although presented differently and for only 12 radionuclides DCCs derived by a different method Allowed participation of Russian institutes leading to EPIC effects database www. radioecology-exchange. org

Chronology ¥ Europe ¥ ERICA (EC) 2004 -2007 Developed the CR and effects (FREDERICA) databases from FASSET & EPIC ¥ Developed FASSET dosimetry methodology ¥ Adapted ‘guidance’ for selecting missing CRs from EA SP 1 a ¥ Output - the ERICA Tool implementing the ERICA Integrated Approach ¥ More generic ecosystem types (because of lack of data) than FASSET and adapted reference organism list (to encapsulate European protect species & remove some unjustified sub-categories) ¥ Derived 10 µGy/h screening dose rate (by SSD) ¥ Being maintained and updated ¥ www. radioecology-exchange. org

d n a Chronology T to E S on S i t ¥ Europe A n F e ) t h s t n ¥ ERICA (EC) 2004 -2007 r i o e band aeffects edatabases t e (FREDERICA) t h e Developed the CR s t t e m – d s d a from FASSET & EPIC e r e e t A t d r a s r a e E o p r Developed FASSET dosimetry methodology ( v e p & o p e p A selecting r u u‘guidance’ s u Adapted missing CRs from EA p ts ICfor s o s d m i A R p T SP 1 a t C ou o E EC ing nd I - tthe ERICA Tool implementing the ERICA n a T ER ICOutput e e approach a O e t integrated n v r P a R o o c i E More d (because t P ecosystem s m generic l types of lack of data) c h a e C / l n reference E Gyand adapted than FASSET organism list (to e o s i t protect i µ encapsulate European species & remove some a d t 0 d da 1 sub-categories) unjustified a g and updated n Being maintained i us ¥ ¥ ¥ www. radioecology-exchange. org

Chronology ¥ International ¥ IAEA (2009 -) Wildlife transfer parameter handbook (in-press) ¥ 2013 - initiate group to draft Volume III of ‘Generic models for use in assessing the impact of discharges of radioactive substances to the environment’ Volume III considers wildlife. ¥ ¥ ICRP Committee 5 (2005 -) Provided tabulated DCC values (using ERICA methodology) and summarised effects information (ICRP-108) ¥ Report presenting CR values for RAPs (ICRP-114) ¥ www. radioecology-exchange. org

Chronology ¥ USA ¥ USDOE Graded Approach (2002) Initially supported by BCG-Calculator spreadsheet model. Still available – but replaced by: ¥ RESRAD-BIOTA ¥ ¥ ¥ Limited and conservative CR values for generic organisms RESRAD-BIOTA v 1. 5 (2009) includes values from the ERICA (original) CR database in supporting documentation for application in uncertainty analysis www. ceh. ac. uk/PROTECT

So don’t. . . ¥ Use out of date approaches unless you can justify why they have been used, e. g. : OK to use R&D 128 for noble gases ¥ Not OK to use FASSET CR values because they offer more ‘refined’ reference organism list/ecosystem range ¥ . . but do be aware that this is an evolving area www. radioecology-exchange. org

Misuse of default values ¥ To serve the purpose for which they were intended RESRAD-BIOTA, R&D 128(SP 1 a) and the ERICA Tool give a complete list of radionuclide-organism transfer parameters. ERICA Tool and R&D 128 missing values derived using ‘guidance’ approaches. These should not be blindly used in higher tier assessments nor should they be picked out for use in other models/recommendations without being clearly identified as such ¥ RESRAD-BIOTA Biv (=CR) values very generic and conservative ¥ www. radioecology-exchange. org

Misuse of default values ¥ ERICA and R&D 128 both clearly identify values which have been derived via guidance approach rather than data ¥ But have been taken as ‘values’ www. radioecology-exchange. org

Double accounting ¥ Some scope for ‘double accounting’ associated with daughter product half-life cut -offs ¥ e. g. R&D 128 includes all 234 Th and 234 U in DCCs for 238 U ¥ ¥ Entering both 234 Th and 238 U activity concentrations would over estimate dose rates RESRAD-BIOTA and ERICA both offer the user the opportunity to do similar www. ceh. ac. uk/PROTECT

t Double accounting o n e r a y / l l e ¥ Some scope for ‘double accounting’ r cia l a a s e r r associated with daughter product half-life cut p u e t s t a e h n g s -offs f u C o a C d s t 234 U in DCCs t D ¥ e. g. R&D 128 includes all Th and n a t e l h u m s for 238 U d w efa s s e n e d d 234 Th and 238 Uliactivity concentrations s a Entering both t n c s i s u a r d n r e would over estimate dose rates e o o d i f d n d t u l a U¥ RESRAD-BIOTA n r c and ERICA both offer the user a t n i r o the opportunity to do similar p im ¥ www. ceh. ac. uk/PROTECT

Summary Do not use/accept out of date approaches – unless justified ¥ Be aware of potential changes as a consequence of recent transfer parameter reviews & forthcoming ERICA update ¥ Ensure no misuse of default values provided by various approaches ¥ ¥ ¥ Use alternatives where justified There are differences between approaches ¥ ¥ ¥ Dosimetric methods tend to give similar results Transfer parameters can add significant variation Screening tiers (see http: //dx. doi. org/10. 1088/09524746/30/2/S 04) www. radioecology-exchange. org