PROTECTFP PROTECT recommendations – application in practice

PROTECTFP Outline Overview of approaches to assessment/available assessment tools Uncertainty/variability in model predictions Put the PROTECT benchmark values into context of results of existing environmental assessments Optimisation Revisit concepts Introduce breakouts

IAEA EMRAS Biota Working Group

Internal dose rates Internal dose estimates generally all within 20 % of mean (of predictions) –exception being for U-238: two approaches including U-234 as daughter (resulting in 2x higher DCC)

External dose rates Considerably more variable between models – especially for β- emitters

e.g. Duck on soil surface predictions for Sr-90

External dose rates More variable between models – especially for β- emitters –Especially H-3 & C-14 (e.g. external DCC for duck on soil for H-3 ranged 0 to 5E-11) Media assumptions (density and distribution of contamination) can be seen to result in some variation Differences in approaches that do not matter: –use of specific geometries v’s nearest default –number of emissions assumed

Predicted activity concentrations Considerable variation between predictions (3- orders of magnitude being common) Pu-239

Predicted activity concentrations Some variation can be understood, e.g.: –Missing value guidance approach often give comparatively high estimates (often for little studied organisms) –Site specific (and national) data –Some approaches include reindeer data in derivation of CRs leading to high predictions for mammals (especially Po-210) Tc-99 predictions had least variation –Very few data and all using similar approach

PROTECTFP PROTECT WP2 comparison of screening Tier predictions Comparison of initial screening tier against the same screening level (for example USDOE values adopted) –Limiting RQs compared

PROTECTFP Terrestrial RESRAD-BIOTA & ERICA-Tool + EA R&D128 Variation appears to be predominantly due to transfer components

PROTECTFP Example - England & Wales ‘Habitats’ assessments Assessed 715 radioactive discharge authorisations Screening level of 5 µG/h used 600 authorisations did not require assessment more detailed than initial conservative level (i.e. estimate < 5 µG/h) Only 9 sites would exceed PROTECT proposed 10 µG/h generic screening level One site exceeds 450 µG/h Most exposed organism at this site = marine mammal (very conservative assessment)

PROTECTFP Example assessment results Used data from SENES 2007 (report for WNA) [+ some additional ERICA case study site data + EcoMetric Chalk River Lab. report] Considers results of published assessments for range of sites Used presented media activity concentration data to run through ERICA Tool (Tier 2 – default parameters) to determine weighted whole-body absorbed dose rates Most media activity concentrations presented as ‘upper bound’ or maximums Note not all assessments considered by SENES (& ERICA) were complete assessments

PROTECTFP Terrestrial assessments Marine assessments

PROTECTFP Freshwater assessments

PROTECTFP AECL Chalk River Laboratories

PROTECTFP AECL Chalk River Laboratories

PROTECTFP Summary Generic screening value (10 µGy/h) is likely to identify sites of negligible risk (EA Habitats assessments) The ‘taxonomic’ screening level for ‘non- vertebrates’ (450 µGy/h) attempts to account for radiosensitivity – in example assessments appears to be fit for purpose –Identifying sites requiring more refined assessment