icrp c5 update k.a. higley – protect meeting, vienna austria june, 2007

ICRP C5 Update

K.A. Higley – PROTECT Meeting, Vienna Austria

June, 2007

Acknowledgements

• Most of the following slides have been “borrowed” from previous presentations of other C5 members

• If there are – mistakes, they are mine– overstatements, they are also mine

• If I got it completely right, it is because of the brilliance of my C5 colleagues

ICRP Committee 5 membership

RJ Pentreath (chair) UKCM Larsson (vice-chair) SwedenK Higley (secretary) USAP Strand NorwayA Johnston AustraliaA Real SpainF Brechignac FranceK Sakai JapanG Pröhl Germany

ICRP C5

• Concerned with radiological protection of the environment.

• Aim: development and application of approaches to environmental protection that are: – Compatible with those for radiological protection of

man, and– With those for protection of the environment from

other potential hazards.

Directions of C5 Work

• Develop a framework for the assessment of radiation exposure and effects on non-human species:– For planned, existing, and emergency exposure

situations.– That will serve as a benchmark for international and

individual national approaches to environmental protection

– And that will parallel the framework for human radiation protection.

• Done in an open and transparent manner.

Commonalities, RP (hum) and RP (env)

Reference Person

Environmental radionuclide concentration(s)

Reference Animals and Plants

Dose limits, constraints,reference levels

Decision-making regarding public health and environment for the same environmental situation

Derived Consideration Levels

Planned, existing and emergency exposure situations

C5 Four Year Plan, Major Documents

• Reference Animals and Plants (2007)– Supporting database (transfer, background, etc)– Radiation dosimetry – Radiation effects

• Radiation weighting factors (2008)• Commonality of RAPs approach to other

environmental protection efforts (2008-9)• Will build on updated scientific information and

recent methodological achievements (EC projects, UNSCEAR……

High Level Overview

• A reference animal or plant is a hypothetical entity,

• With the assumed basic characteristics of a specific type of animal or plant, as described to the generality of the taxonomic level of family,

• With precisely defined anatomical, physiological, and life-history properties

• That can be used for the purposes of relating exposure to dose, and dose to effects, for that type of living organism.

Reference Animals and Plants

Reference Animals and Plants• Deer• Rat• Bee• Earthworm

• Duck• Frog• Trout

• Marine Flatfish• Crab

• Pine Tree• Grass• Seaweed

Legislation on wildlife protection

Toxicity testing

Human resource

Data on radionuclide accumulation

Data on radiation effects

Amenable to further

study

Public resonance

Rat + +++ ++ +++ +++ +

Duck +++ + + + +++ +++

Frog ++ + + + ++ ++

Salmonid fish ++ +++ +++ + +++ +++ +++

Flat fish + +++ +++ ++ ++ +

Bee + + ++ ++ + +++ ++

Crab + +++ +++ + ++ ++

Deer + ++ + + + +++

Earthworm +++ ++ + +++ ++

Pine tree + ++ ++ +++ +++ +++

Grass + ++ ++ +++ +++ ++

Seaweed + +++ + ++ ++

Criteria for Selection of RAPs

Consideration of Exposure Situations and Computation of DCCs

Small burrowing mammal exposed from a planar source at the surface of the soil

Computational ”animal” with ”liver” and ”testes”

Overview of FRED(ERICA) Effects Data; Access via www.erica-project.org

Ecosystem

References# Data % Effect

Total Number

% External Internal Other

Terrestrial (579)

19,983 72.6

Acute 12,273 61.4 11564 288 421

Chronic 6,795 34.0 3449 344 3002

Transitory 913 4.57 670 40 203

Not Stated 2 0.03 0 0 2

Freshwater (195)

6067 22.0

Acute 4,526 74.6 4058 97 371

Chronic 1,484 24.5 970 20 494

Transitory 54 0.89 12 2 40

Not Stated 3 0.01 0 0 3

Marine (45) 1470 5.4

Acute 1116 75.9 995 58 63

Chronic 353 24.1 286 0 67

Transitory 0 0 0 0 0

Not Stated 1 0 0 0 1

Natural Background*

ECOSYSTEMNON-

WEIGHTED

µGy h-1

WEIGHTEDa

µGy h-1

Marine 0.04 – 2.8 0.08 – 9.9

Freshwater 0.09 – 6.1 0.65 - 44

Terrestrial0.023 – 0.09

(external)

aIncludes weighting factors for high LET radiation

*Brown et al.; Gomez-Ros et al. 2004. Journal of Radiological Protection, 24:4A, pp 63 - 88

Derived Consideration Levels – Individual Effects

Derived Consideration Levels - Ecosystems

Derived Consideration Levels - Decisions

In Depth Status Report

STATUS: Existing Information on Radiation Effects for RAPs

Data on RAPS organism available

Data on RAPS-related organism available

No data available

Preliminary Data Survey

Availability of Acute Data

Reference Organism Morbidity MortalityReproductive

CapacityMutation

Deer

Rat

Duck

Frog

Trout

Marine Flatfish

Bee

Crab

Earthworm

Pine Tree

Grass

Seaweed

=data available = related data maybe available = no data available

Availability of Chronic Data

Reference Organism Morbidity MortalityReproductive

CapacityMutation

Deer

Rat

Duck

Frog

Trout

Marine Flatfish

Bee

Crab

Earthworm

Pine Tree

Grass

Seaweed

=data available = related data maybe available = no data available

Data on RAPS organism available

Data on RAPS-related organism available

No data available

How to Proceed

Scaling functions?

STATUS: Dosimetry for RAPS

Objectives

• Select approach to estimate Dose Per Unit Concentration (DPUC) – Kinetics not taken into account– Doses to organs not explicitly considered– Consider simple geometries

• Spheres, ellipsoids, cylinders

• Calculate DPUC values for ICRP RAPs – Average dose rate for the whole body per unit activity

concentration • In the organisms, or • Surrounding media.

Dose Concept

• Absorbed dose– Dose equivalent and effective doses as used for

humans not applicable– Radiation weighting factors under discussion

• Absorbed fraction – Fraction of energy emitted by a radiation source that

is absorbed within the target tissue, organ or organism

• Homogeneous medium, organism immersed in water– Dint = E * AF(E)– Dext = E * [1-AF(E)]

Influence of shape

• Internal exposure– AF spheres – AF for various shapes– Interpolation

• Shape• Mass• Energy• => Enables estimations for a wide range of ellipsoids

• External exposure– DCCs for spheres– etc.

Absorbed fractions for photons as a function of mass and energy for spheres

Absorbed fractions for electrons as a function of mass and energy for spheres

10-2

10-1

100

10-1

10010-3

10-210-1

100101

102103

104105

106

AF

E (MeV)

Mas

s (g)

Electron sources in spheres

AF for non-spherical organisms:10 keV photons and electrons

AF for non-spherical organisms:100 keV photons and electrons

External exposure

• Terrestrial RAPs– Based and detailed MC calculations for specified

geometries• On-soil:

– Planar source on the soil with a surface roughness of 3 mm,

– Volume source with a thickness of 10 cm,

• In-soil:• Middle of a volume source with a thickness of 50 cm

• Aquatic– In-water– On-water

Derived Consideration Concentrations (DCCs)

• In Progress

• All RAPs– Partly for different habitats

• 75 radionuclides– Daughters included if half-life < 10 d

• External and internal exposure

STATUS: Supporting Database

Concentration and transfer data used in the derivation of external and internal dose-rates for RAPs

Objective

• Derive a reference set of – Values for naturally occurring radionuclides in sea

water, freshwater, sediment and soil from which to calculate the reference external background dose rates for RAPs.

– Values for naturally occurring nuclides on a whole body basis from which to calulate internal reference background dose rates for RAPs.

– Transfer factors for anthropogenic radionuclides to allow whole body activity concentrations and thereby internal dose rates to be derived for RAPs.

Selection of radionuclides

• For artificial radionuclides, equilibrium concentration ratios (CRs) have been derived for the following: – Ag, Am, C, Cd, Ce, Cl, Cm, Co, Cs, Eu, H, I, Mn,

Nb, Ni, Np, P, Pu, Ru, S, Sb, Se, Sr, Tc, Zr

• For naturally-occurring radionuclides, activity concentrations in RAPs and their environment were derived for all radionuclides in U-238 and Th-232 decay chains with half-life > 10 days; and for other important primordial and cosmogenic radionuclides

)kg/Bq(mediainionconcentratActivity

.)w.fkg/Bq(biotainionconcentratActivityCR

Terrestrial CRs for RAPs – data coverageNuclide Earthworm Bee Wild grass Pine tree Rat Deer Ag - RO √ - - - C √ - √ √ √ √ Cd √ RO √ RO - - Ce (√) - - - - - Cl √ - (√) (√) - - Cm - - √ RO - - Co - RO √ RO √ RO Eu (√) - - - - - H (√) - (√) - (√) (√) I √ - √ - - - Mn √ - √ RO RO RO Nb (√) - RO - RO RO Ni √ RO RO RO RO RO Np - - √ - - - P - - - - - - Pu ? Ru - RO (√) - - - S - RO RO RO RO RO Sb (√) - RO - - - Se (√) - RO - RO RO Tc - - RO - - - Te - - - - RO RO Zr - - - RO - - √ = data available; (√) = < 5 data points RO = data available for reference organism (but not RAP) - = no data

Natural radionuclides considered

* Assumed for dosimetric purposes for progeny with t1/2 less than 10 days.

Radionuclides Natural sources Half-life (t1/2) Progeny in equilibrium* C-14 Cosmic 5730 years -

H-3 Cosmic 12 years -

K-40 Primordial 1.3 x 109 years -

Pb-210 U-238 series 22 years Bi-210

Po-210 U-238 series 138 days -

Ra-226 U-238 series 1600 years Rn-222, Po-218, Pb-214, Bi-214, Po-214

Ra-228 Th-232 series 5.7 years Ac-228

Rb-87 Primordial 4.9 x 1010 years -

Th-228 Th-232 series 1.9 years Ra-224, Rn-220, Po-216, Pb-212, Bi-212, Po-212, Tl-208

Th-230 U-238 series 80 000 years -

Th-232 Th-232 series 1.4 x 1010 years -

Th-234 U-238 series 24 days Pa-234

U-234 U-238 series 2.5 x 105 years -

U-235 U-235 series 7.0 x 108 years Th-231

U-238 U-238 series 4.5 x 109 years -

ACTION 1 : External dose-rates from naturally occurring radionuclides

External dose-rates from naturally occurring radionuclides

• Marine – Raw data collated. Preliminary typical values derived.

• Terrestrial – Work in progress– e.g. World generic soil values (UNSCEAR,

2000)• Freshwater – Work in progress. Data available

J.E. Brown, S.R. Jones , R. Saxén, H.Thørring and J. Vives i Batlle (2004). Radiation doses to aquatic organisms from natural radionuclides. Journal of Radiological Protection, 24, pp. A63-A77.

UNSCEAR (2000).Sources and effects of ionising radiation

Concentrations of naturally occuring radionuclides in seawater (Bq/m3)

Radionuclide Typical ~Range Comments C-14 6 General waters

H-3 50 22 - 110 General waters

K-40 18000 12 000 Bq/m3 in older publications Pb-210 2 0.3 - 5 Slightly lower mean for coastal waters

Po-210 2 0.1 - 4 Typical value about 1 Bq/m3 for surface and coastal waters

Ra-226 1.5 3.4

0.7 - 7 0.2 - 20

Ocean (surface) Coastal waters

Ra-228

0.5 -

0.02 - 4 0.5 - 20

Ocean Coastal

Rb-87 110 General waters

Th-228 0.06 0.3

0.0065 - 0.35 0.05 - 0.75

Ocean Coastal

Th-230 0.015 0.15

0.0015 - 0.07 0.035 - 0.55

Ocean Coastal

Th-232 0.004 0.08

0.0004 - 0.1 0.009 - 0.9

Ocean Coastal

Th-234 - No data at present

U-234 47 General waters

U-235 1.9 General waters

U-238 41 12 - 80 General waters

Review based on Bowen (1979), IAEA (1988a),IAEA (1988b),IAEA (1990), Cherry & Shannon (1974), Woodhead (1973), Brown et al (2004)

• Activity concentrations depend on underlying sediment type, e.g. clay content strongly influences K-40 concentrations. Separate sediments into sand, silt, clay where appropriate and data coverage sufficient ?

Radionuclide Typical Range Comment C-14 7 3.5-14 H-3 0.05 K-40 500 63-1200 Depends on clay content, predominant contributor to

external exposures Pb-210 150 20-518 Enhanced levels of unsupported Pb-210 in surface

sediments Po-210 150 5-900 Enhanced levels of unsupported Po-210 in surface

sediments following ingrowth from Pb-210 Ra-226 (30) 6-1720 Pb-214 and Bi-214 will contribute to external exposure Ra-228 (20) 18-83 External exposure likely to be insignificant (minor Ac-

228) Rb-87 120 Derived from stable element data for ’mean’ sediment

and isotopic abundance Th-228 20 5-40 Contributions from Pb-2312, Bi-212 and Tl-208 Th-230 150 1-2400 External exposure likely to be insignificant Th-232 10 4-96 External exposure likely to be insignificant Th-234 (10) = U-238 concentration U-234 External exposure likely to be insignificant U-235 1 0.4-3 U-235 decay chain not considered in detail U-238 10 1-63 External exposure likely to be insignificant

Review based on : Baxter (1983); BNFL(1994); Bowen(1979); Brown (1997); Brown et al. (2004); Grøttheim (1999); Hamilton et al. (1994); Holm & Fukai (1986); IAEA (1988a); Kershaw et al. (1992); McCartney et al. (1990); McDonald et al. (1991);Van der Heijde et al. (1990);Walker & Rose (1990).

Concentrations of naturally occuring radionuclides in marine sediment (Bq/kg d.w.)

Marine – seawater and sediments

• Broader review necessary ?– Focus on nuclides important from an exposure

perspective ?

• Summarised or generic values can be derived– (statistically) summarised values difficult to derive

because original information often provided as typical or representative values.

ACTION 2 : Set of natural radionuclide concentrations for internal dose rates

Set Of Natural Radionuclide Concentrations For Internal Dose Rates

• Marine – Starting from data collated for Brown et al. (2004).

• Database further developed and expanded• Contains approximately 1500 data.

– Macroalgae (n=669), – Crustaceans (n=374), – Fish (n=373)

• Most data are Po-210

• Terrestrial and freshwater not considered here

All compiled data (RO coverage)

0

100

200

300

400

500

600

700

C-14 H-3 K-40 Pb-210 Po-210 Ra-226 Ra-228 Rb-87 Th-228 Th-230 Th-232 U-234 U-235 U-238

Radionuclide

Nu

mb

er o

f sa

mp

les

Fish

Crustaceans

Macroalgae

Marine RAPs

60 %

40 % Brown algae

Other macroalgae

75 %

25 %

Cancer pagarus

Other crustaceans

12 %

88 %

Flatfish

Other types of fish

Jklfhd-lsdgfsjd

Hj.hsdjkgfhksd

Radionuclide Brown algae Cancer pagarus Flatfish C-14 RO RO RO

H-3 RO RO RO

K-40 √ RO RO Pb-210 √ √ √ Po-210 √ √ √ Ra-226 √ (√) √ Ra-228 √ - RO Rb-87 √ RO RO Th-228 √ (√) (√) Th-230 √ (√) (√) Th-232 √ (√) (√) Th-234 - - - U-234 √ (√) (√) U-235 √ (√) (√) U-238 √ (√) (√) √ = data available (In brackets – only limited amount of data n<3)

RO = data available for ERICA reference organisms (but not RAPs)

- = No data

Macroalgae

Crustaceans

Fish

Available data (example)

Reference organism Mean SD N Range Comments Brown algae 2.0 1.2 126 0.5 - 8.5

Cancer pagarus 18 11 55 1.4 - 43

Flatfish 17 13 20 3.9 - 51 Muscle data corrected using a factor of 8

Reference organism Mean SD N Range Comments Macroalgae 2.4 2.2 156 0.2 - 15

Crustacean 54 110 210 0.4 - 920

Fish 32 81 225 0.3 - 760 Muscle data corrected using a factor of 8

Concentrations of Polonium-210 (Bq/kg FW) in corresponding ERICA reference organisms (ROs)

Concentrations of Polonium-210 (Bq/kg FW) in RAPs

ACTION 3: CRs for Deriving Internal Activity Concentrations of Artificial Radionuclides

CRs for Deriving Internal Activity Concentrations of Artificial Radionuclides

• Marine – Comprehensive database created by NRPA

• Terrestrial – Preliminary summary table provided by CEH. NRPA working on database in conjunction with CEH

• Freshwater – Data made available from STUK. Further work necessary (Data not presented here).

Marine CRs – Macroalgae

OtherMacroalgae

Brownalgae Co

PuCs

SrCe

Red, green and brown macroalgae

Brown algae

Cs

Pu

Tc

Sr

Co

Macroalgae Brown algae

Number of samples 1560 307

> 5% Cs, Pu, Tc, Sr, Co Cs, Pu, Co, Sr, Ce Data

coverage < 5% Ag, Am, Cd, Ce, Cm, Eu, I, Mn, Nb, Ni, Np, Ru, Sb, Zr

Ag, Am, Cd, Eu, I, Mn, Ni, Ru, Sb, Tc, Zr

Marine CRs - Crustaceans

Other crustaceans

CancerPagarus

Cs

Am

Pu

Tc

All crustaceans Cancer pagarus

Cs

Tc

Pu

Crustaceans Cancer pagarus

Number of samples 555 120

> 5% Cs, Pu, Tc Cs, Pu, Am, Tc Data

coverage < 5% Am, Cd, Ce, Co, Mn, Nb, Ni, Ru, Sb, Se,Sr, Zr

Marine CRs - Fish

Othertypes of fishes

Flatfish

Cs

Tc

Pu

All fish types Flatfish

Cs

PuSr

Co

Fish Flatfish

Number of samples 2349 385

> 4% Cs, Co, Pu, Sr Cs, Pu, Tc Data

coverage < 4% Ag, Am, Cd, Ce, Eu, Mn, Ni, Ru, Sb, Se, Tc, Zr

Ce, Co, Eu, Sr, Zr

Example

Reference organism Mean SD N Range Comments

Brown algae 51 40 94 5 - 204

Cancer pagarus 17 12 18

Flatfish 57 70 304 5 - 517

Reference organism Mean SD N Range Comments

Macroalgae 118 733 583 5 – 7740

Crustacean 41 83 281 0 - 1305

Fish 86 122 1780 0 - 1800

Cs-137 CF values (Bq/kg FW) for ICRP Raps

Cs-137 CF values (Bq/kg FW) for corresponding ERICA reference organisms

Marine CRs – Fish egg and Fish larvae

Radionuclide

Sr Y Ce Zr Ru P Nb Cs Co C S Mn

Num

ber

of s

ampl

es

0

2

4

6

8

10

Radionuclide

Sr Y Ce Cs Zr Ru P Co S Mn

Nu

mb

er

of s

amp

les

0

2

4

6

8

10Fish egg Fish larvae

The available data is very limited

•Fish egg: n = 45

•Fish larvae: n = 39

Available data (example)

All fish types Turbot Mean N Range Mean N Comments

Fish egg 2 9 1 - 10 1,6 1 -

Fish larvae 2 8 1 - 4 4,3 1 At the age of 96 hours

Sr Concentration factor values for fish egg and fish larvae for all fish types and turbot.

Terrestrial CRs for RAPs

0

500

1000

1500

2000

2500

3000

Nu

mb

er o

f d

ata.

.

Ref. orgs minus RAPs

RAPs

Terrestrial CRs for RAPs – data coverageNuclide Earthworm Bee Wild grass Pine tree Rat Deer Ag - RO √ - - - C √ - √ √ √ √ Cd √ RO √ RO - - Ce (√) - - - - - Cl √ - (√) (√) - - Cm - - √ RO - - Co - RO √ RO √ RO Eu (√) - - - - - H (√) - (√) - (√) (√) I √ - √ - - - Mn √ - √ RO RO RO Nb (√) - RO - RO RO Ni √ RO RO RO RO RO Np - - √ - - - P - - - - - - Pu ? Ru - RO (√) - - - S - RO RO RO RO RO Sb (√) - RO - - - Se (√) - RO - RO RO Tc - - RO - - - Te - - - - RO RO Zr - - - RO - - √ = data available; (√) = < 5 data points RO = data available for reference organism (but not RAP) - = no data

Terrestrial CRs for RAPs - comments

• There are few RAP specific values• Data are for 'adult stage'; ERICA considers terrestrial bird

eggs and has some values derived from terrestrial bird CRs combined with hen diet-egg transfer information (not reported in ICRP database)

• The ERICA CR summary database contains a value for every RO-radionuclide combination. Where data are lacking these were derived using various guidance options. The values derived by this guidance are NOT included in the ICRP summary - i.e. this contains data derived from empirical values only

• FOR H, C, S, P CR defined as whole body activity concentration (fresh weight) to the activity concentration in air (Bq/m3); model derived.

General discussion (CRs)

• Technologically-enhanced radionuclides : CR values e.g. U-238, Ra-226, Po-210, C-14 and H-3 may be useful in a regulatory context.– Can be extracted from existing databases.

• Use RAP specific values or generic RO values ?

• Data gap filling methodology (ERICA) – relevant here ?

STATUS: Radiation Weighting Factors

Radiation Weighting Factors

• Under discussion– FASSET

• Low β: 3• α:10

– UNSCEAR• α:10

STATUS: Commonality of RAPS with other approaches

Bottom-up, toxicological approachBased upon individuals

System structured around some reference(s)Dose-driven (weighted to allow for additivity)

Human

Environment (RAPs)

Single effect endpoint: cancer induction

Several effect endpoints: mortality, morbidity,

reproduction, chromosome damage

Stochastic effects of major concern, LNT model assumption

Deterministic effects of major concern

F. Bréchignac – ICRP Committee 5 Meeting, Corvallis, Oregon, USA, 15-18 August 2006

Raps Approach Consistent With Human Radioprotection

STATUS - OVERALL

Progress to Date

• Two major meetings– Geneva, Sept 05– Corvallis, Aug 06– Next in Germany, 07

• Task groups – Dosimetry– Other??