Presentation is loading. Please wait.

Presentation is loading. Please wait.

PROTECTFP6-036425 Screening tier comparisons ERICA, RESRAD-BIOTA & EA R&D128 Follow-up actions from Vienna workshop.

Similar presentations


Presentation on theme: "PROTECTFP6-036425 Screening tier comparisons ERICA, RESRAD-BIOTA & EA R&D128 Follow-up actions from Vienna workshop."— Presentation transcript:

1 PROTECTFP Screening tier comparisons ERICA, RESRAD-BIOTA & EA R&D128 Follow-up actions from Vienna workshop

2 PROTECTFP Vienna scenario Comparison of the three openly available models – RESRAD-BIOTA, ERICA-Tool & EA R&D128 River receiving mixed radionuclide discharges from multiple sources

3 PROTECTFP Results ERICA – highest dose rate (circa E3 µGy/h) predicted for insect larvae dominated by 234 Th R&D128 – highest dose rate (circa E3 µGy/h) predicted for amphibian dominated by 239 Pu RESRAD-BIOTA – 137 Cs was the only nuclide to result in a risk quotient (RQ) in excess of 1 (for riparian animal)

4 PROTECTFP

5 PROTECT

6 PROTECT Decision to further compare the screening tiers of the three models – 1 Bq per unit media model runs Associated ‘request’: can PROTECT establish the degree of conservatism ?

7 PROTECTFP Screening tiers – similarities/differences (where we think the conservatism is) 2.Comparison of outputs

8 PROTECTFP ERICA-Tool - Tier 1 Recommends enter maximum media activity concentration 95 th percentile environmental media concentration limits (EMCLs) predicted using default transfer parameters pdfs (conservative habitat assumption) –10 µGy h -1 –40 µGy h -1 terrestrial animals / 400 µGy h -1 plants and all aquatic organisms Risk quotients reported for most limiting organism (and media) for each radionuclide and for ecosystem

9 PROTECTFP ERICA-Tool Tier 1 result

10 PROTECTFP ERICA EMCLs EMCL for water – takes into account external exposure from sediment (k d ) or water and internal exposure estimated from water conc. using CR EMCL for sediment - takes into account external exposure from sediment or water (kd) and internal exposure estimated from water conc. (kd) using CR Freshwater EMCLs Cd-109 Sediment = 2.61E4 Bq/kg Water = 51 Bq/l Cs-137 Sediment = 8000 Bq/kg Water = 5.1E-2 Bq/l

11 PROTECTFP ERICA EMCLs

12 PROTECTFP ERICA Tier 2 Organism specific dose rates and RQs (from total predicted dose rate) reported: –Best estimate –Conservative estimate Conservative dose estimated by applying uncertainty factor (UF) to the best estimate, where: –UF 3 ≈ 95 th percentile prediction –UF 5 ≈ 99 th percentile prediction

13 PROTECTFP ERICA Tier 2

14 PROTECTFP ERICA Tier 2 In theory conservative estimate with UF=3 should approximate to Tier 1 result [with same input] and Tier 3 95 th percentile prediction –Generally works: some case where it does not for aquatic ecosystems if input to sediment

15 PROTECTFP Cs-137 BWG Chernobyl A thought on UF =3

16 PROTECTFP RESAD-BIOTA (USDOE) Tier 1 Recommend enter maximum media activity concentration Media activity concentrations compared to biota concentration guidelines (BCG): –Infinitely large/small geometries assumed –100 % in soil; sediment-water interface –Conservative CR (BiV) values (not kd) –1 mGy/d (40 µGy h -1 ) terrestrial & riparian animals / 10 mGy/d (400 µGy h -1 ) terrestrial plants & aquatic animals More limited range of organisms considered than ERICA (which includes e.g. planktons, lichen which tend to have ‘high exposure’ estimates)

17 PROTECTFP RESRAD-BIOTA Tier 1 CRs Aquatic animals – maximum –Predominantly taken from Till & Meyer 1983 maximum of the 84 th %ile from collated data for fish, mollusc or crustacean Terrestrial plants – maximums –Predominantly taken from Till & Meyer 1983 considers food crops, forage & grass Terrestrial/Riparian animals – most derived using kinetic-allometric approach – 95 th %ile

18 PROTECTFP BGCs Terrestrial - Soil & water Aquatic & Riparian - Sediment & water

19 PROTECTFP BGCs Aquatic animals –Sediment - External exposure from sediment –Water – Internal & external exposure from water Riparian animals –Sediment – Internal & external exposure from sediment –Water – Internal & external exposure from water Terrestrial animals –Soil - Internal & external exposure from soil –Water - Internal & external exposure from water Terrestrial plants –Soil - Internal & external exposure from soil –Water - External exposure from water

20 PROTECTFP EA R&D128 - screening As applied – maximum inputs Compares results to 5 µGy h -1 for screening (40 µGy h -1 action level) Default transfer parameters used –Some transfer values are highly conservative

21 PROTECTFP Screening tier predictions Assuming 1 Bq soil/water/sediment Against 40/400 µGy h -1 Terrestrial – freshwater only [RESRAD-BIOTA does not consider marine] Radionuclides common to RESRAD-BIOTA & ERICA-Tool Not H-3 & C-14 for terrestrial: RESRAD-BCGs for soil; ERICA EMCL for air Compared as RQs

22 PROTECTFP Terrestrial RESRAD-BIOTA & ERICA-Tool + EA R&D128

23 PROTECTFP Terrestrial – EA 5 µGy h -1

24 PROTECTFP RQ Min/Max > 10

25 PROTECTFP Freshwater – input to water

26 PROTECTFP RQ Min/Max > 10 ERICA kd’s often comparatively high

27 PROTECTFP Freshwater – input to sediment

28 PROTECTFP RQ Min/Max > 10

29 PROTECTFP Comment Used in basic screening assessments (their envisaged main use) the readily available models can give widely differing results –(yet again) predominantly explained by transfer elements


Download ppt "PROTECTFP6-036425 Screening tier comparisons ERICA, RESRAD-BIOTA & EA R&D128 Follow-up actions from Vienna workshop."

Similar presentations


Ads by Google