How do screening tiers How do screening tiers compare?compare?

• Run RESRAD-BIOTA, ERICA Tool and EA R&D128 against 10 µGy/h screening dose rate

• Data from SENES-WNA report – maximum media activity concentrations = advised input for basic screening level

• Four freshwater and three terrestrial scenarios

Initial screening tier: Tier 1 Initial screening tier: Tier 1 • Designed to be simple and conservative

– User only needs to input media activity concentrations

• Aim - to enable sites of negligible concern to be identified and removed from need for further assessment – with a high degree of confidence

• Envisaged that most sites will only need this level of assessment [i.e. ‘be screened out’]

Tier 1Tier 1• Media concentrations are compared to

predefined concentrations (EMCLs or BCGs) = concentration giving rise to screening dose rate (to most limiting organism)

‘‘Concentration limits’Concentration limits’• Both ERICA Tool & RESRAD-BIOTA use ‘tiered

assessment’ with initial assessment being very simple – minimal input/conservative output [more later]

• Input media concentrations compared to predefined concentrations = media concentration giving rise to screening dose rate – ERICA: ‘environmental media concentration limits’

EMCLs– RESRAD-BIOTA: ‘biota concentration guidelines’

BCGs

ERICA Tool - EMCLsERICA Tool - EMCLsEstimated assuming:• Habitat assumption to maximise exposure• Probability distributions associated with the

default CR and Kd databases were used to determine 5th percentile EMCL

• No conservatism applied to dosimetry

• For aquatic ecosystems EMCL for water includes consideration of external dose from sediment and that for sediment includes external dose from water and biota-water transfer

RESRAD-BIOTA - BCGsRESRAD-BIOTA - BCGsEstimated assuming:

• Infinitely large (internal) and small (external) geometries for dose calculations

• Daughter T1/2’s up to 100 y included

• All terrestrial organisms 100% in soil; aquatic 100% water-sediment interface

• ‘Maximum’ CR values or 95th percentile CR values predicted using a kinetic-allometric approach

Input data - freshwaterInput data - freshwaterActivity concentration (Bq l-1 or Bq kg-1)

FW1 FW2 FW3 FW4

Nuclide Water Sediment Water Sediment Water Water Sediment

3H 5.60x104       2.78x103    

14C         4.81x10-1    

60Co 2.52x10-2 1.59x102     8.51x10-2    

90Sr 1.60x10-1 6.00x102 7.50x10-3 9.60x10-1 2.74x10-1    

106Ru 2.60 2.32x103     8.14x10-1    

131I 1.10x10-1 1.10     1.44x10-1    

137Cs 8.80x10-2 2.08x103 8.50x10-3 8.50 4.44x10-3    

210Po 5.00x10-2 3.70x102       3.70x10-2 1.51x103

234U** 8.00x10-2 2.05x101 2.00 1.00x102   3.05x10-1 2.15x104

234Th*** 8.00x10-2 1.00x102 1.80 9.10x101   3.05x10-1 2.15x104

238U 8.00x10-2 1.00x102 1.80 9.10x101   3.05x10-1 2.15x104

239Pu 9.50x10-5 5.06x101          

241Am 5.00x10-3 5.00x101          

Input data - terrestrialInput data - terrestrialNuclide T1 T2 T3

Soil (Bq kg-1) Air (Bq m-3) Soil (Bq kg-1) Groundwater (Bq m-3)

Soil (Bq kg-1)

3H 6.59x102 4.81x107 7.00x109

14C 4.81x10-1 2.16x103 2.37x106

60Co 4.52x102

90Sr 1.85

137Cs 1.80x102 2.85x101

234U** 6.09x104 6.08

234Th*** 9.40x103 6.08

238U 9.40x103 6.08

239Pu 7.00

EA R&D128+ RESRAD-BIOTA ERICA Tool

Radionuclide

Most exposed group RQ

Most exposed group RQ

Most exposed group RQ

FW1FW1

3H All organisms 5.5x10-2 Riparian animal 2.3x10-2 Phytoplankton 1.6x10-1

60Co Bacteria 9.5x10-3 Aquatic animal 1.9x10-2 Insect larvae 1.3

90SrAmphibian, Duck 4.5x10-2 Riparian animal 1.7x10-1 Insect larvae 4.9x10-2

106Ru Duck 1.8x101 n/i Insect larvae 2.0x101

137Cs Duck 4.2x10-1 Riparian animal 3.0x10-1 Insect larvae 1.7

131I Duck 9.1x10-4 Riparian animal 8.9x10-4 Phytoplankton 5.3x10-3

210Po

Large benthic crustacean, Small benthic crustacean, Benthic mollusc 8.5x101 Aquatic animal 1.5x10-1 Bivalve mollusc 1.8x101

234U n/a Aquatic animal 4.3x10-1 Vascular plant 6.4x101

234Th n/a n/a Insect larvae 8.6x101

238UAmphibian, Duck 1.3x102 Aquatic animal 3.9x10-1 Vascular plant 2.7x102

239Pu Amphibian 3.0x10-1 Riparian animal 9.5x10-4 Phytoplankton 8.0x10-2

241AmAmphibian, Duck 2.5 Aquatic animal 1.2x10-2 Phytoplankton 1.9

SUM 2.4x102 1.5 4.6x102

EA R&D128+ RESRAD-BIOTA ERICA Tool

Radionuclide

Most exposed group RQ

Most exposed group RQ

Most exposed group RQ

FW2FW2

90Sr Duck 5.7x10-4 Riparian animal 3.1x10-3 Insect larvae 2.1x10-3

137Cs Duck 1.7x10-3 Riparian animal 4.3x10-2 Insect larvae 1.1x10-3

234U n/a Aquatic animal 1.1x101 Vascular plant 3.1x102

234Th n/a n/a Insect larvae 1.9x103

238U Duck 1.2x102 Aquatic animal 8.7 Vascular plant 2.4x102

SUM 1.2x102 1.9x101 2.5x103

FreshwaterFreshwater

EA R&D128+ RESRAD-BIOTA ERICA Tool

Radionuclide

Most exposed group RQ

Most exposed group RQ

Most exposed group RQ

FW3FW3

3H All organisms 2.7x10-3 Riparian animal 1.1x10-3 Phytoplankton 8.1x10-3

14C Duck 1.0x10-2 Riparian animal 8.5x10-2 Bird 3.1x10-2

60Co Bacteria 2.6x10-2 Aquatic animal 3.1x10-2 Insect larvae 4.6

90Sr Duck 2.1x10-2 Riparian animal 1.1x10-1 Insect larvae 7.8x10-2

106Ru Duck 6.2x10-1 n/i Insect larvae 6.4

131I Duck 1.2x10-3 Riparian animal 1.2x10-3 Phytoplankton 6.9x10-3

137Cs Duck 8.9x10-4 Riparian animal 1.1x10-2 Insect larvae 8.7x10-2

SUM 6.9x10-1 2.4x10-1 1.1x101

EA R&D128 RESRAD-BIOTA ERICA Tool

RadionuclideMost exposed

group RQMost exposed

group RQMost exposed

group RQ

FW4FW4

210Po

Large benthic crustacean, Small benthic crustacean, Benthic mollusc 3.5x102 Aquatic animal 1.1x10-1 Bivalve mollusc 1.4x101

234U n/a Aquatic animal 1.6 Vascular plant 6.7x104

234Th n/a n/a Insect larvae 3.3x102

238U Duck 2.9x104 Aquatic animal 2.0 Vascular plant 5.7x104

SUM 2.9x104 4.6 1.3x105

TerrestrialTerrestrialEA R&D128 RESRAD-BIOTA ERICA Tool

RadionuclideLimiting organism RQ

Limiting organism RQ

Limiting organism RQ

T1

137Cs Carnivorous mammal

3.6x10-2 Terrestrial animal

9.4x10-1 Mammal (Deer) 5.8x10-2

234U n/a Terrestrial animal

1.3 Lichen & bryophytes

3.7x101

234Th n/a n/a Grasses & Herbs 5.9x10-2

238U Fungi 1.4x102 Terrestrial plant 6.5x10-1 Lichen & bryophytes

6.2

239Pu Fungi 5.8x10-2 Terrestrial plant 6.0x10-4 Lichen & bryophytes

6.4x10-3

SUM 1.4x102 2.9 4.3x101

T2 EA R&D128 RESRAD-BIOTA ERICA Tool

3H Fungi 1.4x10-1 Terrestrial animal

3.3x101 Detritivorous invertebrate

2.5x10-1

14C Seed 6.3x10-3 Terrestrial animal

6.0x10-2 Mammal (Deer) 5.8x10-3

60Co Fungi 5.3x10-2 Terrestrial plant 8.0x10-2 Mammal (Rat) 6.1x10-2

90Sr Carnivorous mammal

5.9x10-4 Terrestrial animal

8.9x10-3 Reptile 4.9x10-3

137Cs Carnivorous mammal

5.7x10-3 Terrestrial animal

1.5x10-1 Mammal (Deer) 9.1x10-3

SUM 2.0x10-1 3.4x101 3.3x10-1

EA R&D128 RESRAD-BIOTA ERICA Tool

Radionuclide

Limiting organism RQ

Limiting organism RQ

Limiting organism RQ

T3

226Ra Fungi 1.8 Terrestrial plant 1.1x10-1 Lichen & bryophytes

1.3x10-1

234U n/a Terrestrial animal

1.3x10-4 Lichen & bryophytes

3.6x10-3

234Th n/a n/a Grasses & Herbs 3.8x10-5

238U Fungi 8.8x10-2 Terrestrial plant 4.2x10-4 Lichen & bryophytes

4.0x10-3

SUM 1.9 1.1x10-1 1.4x10-1

How do screening tiers How do screening tiers compare?compare?

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