MODARIA Working Group 4 Analysis of radioecological data in IAEA Technical Reports Series publications to identify key radionuclides and associated parameter values for human and wildlife assessment
IAEA Parameter value compilations
Objectives Using the recent data compilations: • To identify the most important radionuclides, pathways and parameter values – For different source terms – For different exposure situations • Identify data gaps which matter • Which key radionuclides require a process based approach to modelling Consider both human and wildlife
Approach • Analyse data quantity and quality • Use freely available tools and/or other models • Develop a set of criteria to evaluate importance of parameter values Source terms • Magnitude and importance of total, external and internal • dose Sensitivity of internal and external dose estimates due to • variability of environmental parameter values Builds on, and compliments: Model based Sensitivity analysis Sensitivity EMRAS II WG
Using TRS publications - identify • Which parameter values may be assumed to be generically representative • Which parameter values are not generically representative as they vary significantly due to Ecosystems, agricultural practices, climate • Physico – chemical form, soil characteristics • Life cycle stages • Data quality and quantity • • Which parameter values need more attention Variability – which number to use? •
Variation in transfer coefficient and CR values AMean: 6.1 x10 -3 , SD: 6.3 x10 -3 , n: 288, AMean: 1.1 x 10 -1 , SD: 1.2 x 10 -1 , n: 119, Median: 4.6 x 10 -3 , Kurtosis: 43.4, Median: 8.4 x 10 -2 , Kurtosis: 8.8, p-Value: 0.005 p-Value: 0.005 IAEA 2010 TRS 472
Deriving parameter values For a screening assessment Time, resources, access Look for False positives data Increased costs QC procedures Compile Data quality Assessment data and and quantity find gaps Rejected sources, Increased Untraceable data. Look again, find Fill gaps conservatism derived values Inappropriate data, Decreased Untested analogues, transparency Rarely new data
.... simplification: Most approaches use concentration ratios (CR) -1 Activity concentrat ion in biota whole body (Bq kg fresh weight) CR - 1 - 1 - 3 Activity concentrat ion media (filtered water (Bq l ), soil (Bq kg dry weight ) or air (Bq m ))
IAEA wildlife TRS status • Submitted early 2011 (publication ‘pending’) • CR wo-media values given • Generic Freshwater, Marine, Terrestrial and Brackish water ecosystems • Summarises CR wo-media data for >800 wildlife- element combinations • Values from the initial submitted text available from: http://www.wildlifetransferdatabase.org/
IAEA outputs • TRS transfer to wildlife • TRS paper in press • Online database • Numerous associated papers from EMRAS I and II
TABLE 4.1 1 CONCENTRATION RATIO (CR wo-soil ) VALUES FOR WILDLIFE GROUPS IN TERRESTRIAL ECOSYSTEMS Wildlife Group CR wo-soil References (Bq kg -1 fw whole organism /Bq kg -1 dw soil) AM AMSD GM GMSD Min Max N Ag (Silver) Grasses and herbs 2.9E+0 3.7E+0 1.8E+0 2.7E+0 2.8E-3 9.8E+0 13 162, 212 Lichens and bryophytes 3.0E-2 3.4E-2 2.0E-2 2.5E+0 1.2E-2 1.3E-1 12 348 Shrub 2.1E-2 9.1E-3 1.9E-2 1.5E+0 1.2E-2 3.3E-2 5 348 Al (Aluminium) Lichens and bryophytes 1.1E-1 1.1E-1 7.1E-2 2.4E+0 1.0E-2 4.2E-1 32 348, 355 Shrub 1.9E-2 1.8E-2 1.4E-2 2.2E+0 2.9E-3 1.2E-1 119 347, 348 Am (Americium) Amphibian 1.3E-1 3.4E-2 1.3E-1 1.3E+0 1.0E-1 1.5E-1 22 486 Annelid 1.8E-1 3.0E-1 9.0E-2 3.2E+0 5.2E-2 1.1E+0 13 171, 486, 488 Arachnid 5.7E-2 6.2E-2 3.8E-2 2.4E+0 2.2E-2 1.3E-1 20 170, 488 Arthropod 1.1E-1 2.9E-1 4.0E-2 4.2E+0 1.3E-3 2.0E+0 82 170, 172, 223, 382, 407, 488 Arthropod - detritivorous 9.6E-2 7.5E-2 7.6E-2 2.0E+0 2.0E-2 2.2E-1 29 170, 172, 223, 488 Bird 3.2E-2 1.6E-2 2.8E-2 1.6E+0 1.9E-2 3.8E-2 3 486 Grasses and herbs 1.0E-1 2.9E-1 3.4E-2 4.4E+0 3.6E-3 3.0E-1 65 177, 250, 486 Grasses 1.0E-1 2.9E-1 3.5E-2 4.4E+0 3.6E-3 3.0E-1 63 177, 250, 486 Lichens and bryophytes 1.2E+0 1.7E+0 6.9E-1 2.9E+0 2.0E-1 3.2E+0 3 382, 486 Mammal 3.2E-2 1.0E-1 9.8E-3 4.7E+0 2.6E-4 1.7E-1 139 172, 184, 197, 221, 245, 407, 488 Mammal - Herbivorous 5.4E-2 2.0E-1 1.4E-2 5.2E+0 2.6E-4 1.7E-1 27 184, 407, 488 Mammal - Omnivorous 3.0E-2 5.4E-2 1.5E-2 3.3E+0 3.7E-4 4.5E-2 84 221, 245, 488 Mammal - Rangifer spp. + 2.0E-1 2.4E-1 1.3E-1 2.6E+0 1.6E-1 2.2E-1 9 197 Gastropod 1.4E-1 1.4E-1 1.0E-1 2.2E+0 5.1E-2 2.0E-1 13 486, 488 Reptile - carnivorous a 6.4E-2 3.9E-2 5.5E-2 1.8E+0 1.0E-3 8.6E-2 16 407, 486
ICRP RAPs RAP Family Bee Apidea Brown Seaweed Fucaceae 12 RAPs Crab Cancridae 39 elements Deer Cervidae Duck Anatidae Earthworm Lumbricidae Flatfish Pleuronectidae Frog Ranidae Pine Tree Pinaceae Rat Muridae Trout Salmonidae Wild Grass Poaceae
ICRP Transfer compilation
Data gaps
Human foodchain • Animal products Sheep Element Beef Goat meat Pork Poultry Egg Cow milk Goat milk Sheep milk meat Ag 1 Am 1 1 1 1 2 Ba 2 1 2 1 15 3 1 Be 1 Ca 3 2 1 15 12 St Cd 8 1 2 8 1 1 Ce 1 1 6 1 Cl 1 Co 4 2 2 2 4 1 2 Cr 3 2 1 Cs 58 41 11 22 13 11 288 28 28 Fe 4 1 2 7 St St I 5 1 2 3 4 104 24 7 La 3 Mn 2 1 1 2 3 4 St 1 Mo 1 1 3 7 4 Na 2 1 1 2 7 St 1 Nb 1 1 1 1 1 1 Ni 2 2 1 Np 1 P 1 1 1 St St St Pb 5 2 15 St 1 1 4 2 Pu 5 2 2 n/a 1 Ra 1 11 Ru 3 2 1 1 6 S 3 1 12 St Sb 2 3 Se 1 4 4 12 2 Sr 35 25 8 12 7 9 154 21 4 Te 1 1 1 1 11 1 1 Th 6 3 U 3 2 2 2 3 1 W 7 Y 1 1 Zn 6 6 2 3 4 8 St St Zr 1 1 1 1 6 1
Wildlife: eg. terrestrial Radionuclide Grasses Lichens & Shrub Annelid Tree Mammal Mollusc Arthopod Bird Reptile Amphibian Arachnid & Herbs Bryophytes Cs Pb Am Sr Cd Pu Ni U Po Ru Mn Th Cl Co Se Sb Ce Eu I Tc Ag Cm Zr Nb Np P S Te n≤ 10 n>10<20 n>20<100 n≥ 100
ICRP RAPs CR values Based on data
Need to fill data gaps? So – an argument for lots more data collection?? more CR wo-media values ? more mechanistic approach ? weighted absorbed dose • Magnitude of internal dose • Proportion of internal dose Evaluated for terrestrial RAPs • ERICA Tool tier 2 • Defaulting weighting factors (low beta 3; alpha 10) – ICRP RAP CR wo-soil values – CR wo-soil =1 values
μ Gy/h per Bq/kg dw soil 0.0E+0 3.0E-4 6.0E-4 9.0E-4 1.2E-3 1.5E-3 Mammal rat Th-231 Th-234 Th-228 Co-60 external internal Co-58 Ra-228 Cs-136 Cs-134 Th-227 Cs-137 Co-57 U-235 Am-241 Pb-210 μ Gy/h per Bq/kg dw soil 6.5E-3 Ra-226 0.0E+0 3.0E-4 6.0E-4 9.0E-4 1.2E-3 1.5E-3 Th-230 Th-232 U-234 U-238 Cs-136 Mammal deer Pu-241 Cs-135 Cs-134 Po-210 Pu-238 Pu-239 Cs-137 Pu-240 Sr-89 Pu-241 Sr-90 Am-241 external internal Cs-135 Pu-238 Pu-239 Pu-240 Sr-89 Sr-90
μ Gy/h per Bq/kg dw soil 0.0E+0 6.0E-4 1.2E-3 1.8E-3 2.4E-3 3.0E-3 Nb-95 Nb-94 Eu-152 Eu-154 Mn-54 Sb-124 Ce-141 internal Sb-125 Cs-136 Cs-134 Earthworm Ce-144 Cs-137 I-132 I-131 I-133 Se-75 Zn-65 I-125 I-129 Ni-59 U-235 Sr-89 Cd-109 Pb-210 Cl-36 Am-241 3.5E-2 Cs-135 Ni-63 Po-210 Se-79 Sr-90 U-234 U-238
Outcome: • Big variation in importance of internal compared with external exposure • direct comparison of internal dose estimates for RAPs limited by o small number of CR wo-soil values o few data for many CR wo-soil values • so difficult to identify RAP CR wo-soil values as low or high priority for further data collection. eg. the relatively high internal 241 Am dose in Earthworm partially due to a high CR wo-soil value with n=1
But no data for many combinations ASSUME CR WO-SOIL =1 • used to conservatively assess the relative importance of internal dose • Assumed occupancy factors which minimized external dose • Not always conservative – so some element-RAP combinations excluded
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