TREE project, Challenges and Future Updates

Radiation Protection of the Environment (Environment Agency Course, July 2015)

•Funded through RATE programme by NERC, EA & RWM Ltd.

• Objective: to reduce uncertainty in estimating the risk, to humans and wildlife, associated with exposure to radioactivity and to reduce unnecessary conservatism in risk calculations

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Challenge – transfer

CR pragmatic, but …..

• Highly variable

• No data for many wildlife-radionuclide combinations

Amphibian

Arthro

podsBird

s

Grasse

s

Mammals

ReptileTre

e10.0

100.0

1000.0

10000.0Sr CRs IAEA TRS479 Max:Min

ICRP Pub-114

Alternative model?

Alternative model? Cs by genus

MossMoss

FungiMoss

MossMoss

MossMoss

MossMoss

Reindeer

Ericace

aeFungi

Lichen

Canid

Ericace

aeFungi

ReptileMoss

Moss

RodentGrass

Moss

Lichen

Asterales

Rosales

Malpighiales

Asterales

Grass

Caryophyll

alesGrass

Vitales

Celastrales

GentianalesGrass

Asterales

Bird

Ericales

Asterales

Bird

Asterales

Myrtales

Grass

Asterales

Asterales

Rosales

Sapindales

Asterales

Bird

Caryophyll

ales1.20E-04

1.20E-03

1.20E-02

1.20E-01

1.20E+00

1.20E+01Top 25

Bottom 25

REML adjusted mean

Cs – freshwater fish

10 100 1000 1000010

100

1000

10000

Abramis brama Esox luciusRutilus rutilus Salmo truttaSander lucioperca Coregonus albulaCoregonus lavaretus Other Cyprinidae

Cs-137 Bq/kg (FW) measured

Cs-1

37

Bq

/kg

(F

W)

pre

dic

ted

R2=0.83; slope=0.98±0.04

Challenge – exposure assessment

Current assumption used in estimating dose fit for purpose?

What will TREE do? Current simplistic assumptions ignore how

animals utilise their environment = conservative?

Challenge - effects

Chernobyl – radiation effects on invertebrates

Into context

ERICA ‘no effect level’

Into context

ERICA ‘no effect level’

ICRP ‘expect effects’

Into context

ERICA ‘no effect level’

UK natural background

ICRP ‘expect effects’

Into context

ERICA ‘no effect level’

UK natural background

ICRP ‘expect effects’

Terrestrial population ‘no-effect’

Japan butterflies

Butterfly larvae fed plants harvested from Fukushima evacuated area

LD50 = 1.9 Bq (?!)

Japan butterflies

Butterfly larvae fed plants harvested from Fukushima evacuated area

LD50 = 1.9 Bq (?!)

LD50 equates to a maximum of c. 8µGy/h Below ‘no-effect’ and in natural background

range?

Japan butterflies

Butterfly larvae fed plants harvested from Fukushima evacuated area

LD50 = 1.9 Bq (?!)

LD50 equates to a maximum of c. 8µGy/h Below ‘no-effect’ and in natural background

range?

From previous studies LD50 for sub-adults ≥ 1 Gy

?

What isTREE doing?

Wildlife cameras – estimate abundance of medium-large mammals

Controlled laboratory and parallel field studies

Future updates of the ERICA Tool

Multi site/time period entry capability Continue to maintain the Wildlife Transfer

Database and update ERICA as appropriate Revise dosimetry approach to be the same

as that used by ICRP and IAEA in forthcoming publications?

Add noble gases? Consider IAEA and ICRP developments

IAEA activities

Updating SRS-19 report: Volume 3 will include non-human biota

Somethings different to ERICA: Direct deposition to vegetation surface (and

subsequent consumption) included Dosimetry – all daughters addressed individually

(no <10d rule) CRs corrected for radioactive decay

ICRP activities

RAPs to representative organisms

RAPs update

Scenarios

Further guidance on application of DCRLs in existing and emergency exposure situations

Trip to Chernobyl?

Trip to Chernobyl?