Transcript David Copplestone & Nick Beresford Centre for Ecology & Hydrology - Lancaster 27th – 29th June 2012 ERICA project objective “to provide and apply.

David Copplestone & Nick Beresford
Centre for Ecology & Hydrology - Lancaster
27th – 29th June 2012
ERICA project objective
“to provide and apply an integrated approach of addressing scientific,
managerial and societal issues surrounding environmental effects of
ionising contamination, at a community level, with emphasis on biota
and ecosystems”
The ERICA Tool (http://www.erica-tool.com/) is the freely available
software which implements the ERICA integrated approach.
To download Tool:
http://www.project.facilia.se/erica/download.html
Well documented:
https://wiki.ceh.ac.uk/display/rpemain/ERICA+reports
Considers terrestrial, freshwater and marine ecosystems
ERICA flow chart
Management
Plan
Assessment Tool
Characterisation
Exit
Stakeholder Involvement
Problem formulation
Issues
Tier 1
Concentration screening value
Tier 2
Dose rate screening value
and
options
Tier 3
Site-specific
Probabilistic analysis
Evaluation of
assessment
Detailed analysis and
evaluation of data. Interaction
and supplementation with all
relevant databases
Extrapolation
(e.g. population, ecosystem)
Exit
ERICA Integrated Approach
www.ceh.ac.uk/PROTECT
April 2006
Elements of assessment
Release
Dispersion model
Media concentration
Transfer model
Wholebody activity
concentrations
Dosimetry model
(external exposure)
Dose rate
Dosimetry model
(internal exposure)
Effects understanding/
numerical benchmark
Risk
www.ceh.ac.uk/PROTECT
What are protection goals?
Clear goals shape Swedish environmental policy
………………………. The overall goal is to pass on to the
next generation a society in which the major environmental
problems have been solved. …………………………….
What are protection goals?
A condition or state desired to be
brought about through a course of
action program. They are usually
qualitative statements that
provide direction for plans and
GOAL
projects. Goals are not specific
numerical limitations, but
conditions or states which can be
obtained through careful planning
and implementation.
The water use goal for the fishery,
established by the Hamilton
Harbour Stakeholder Group, is
"that water quality and fish habitat
should be improved to permit an
edible, naturally-reproducing
fishery for warm water species,
and water and habitat conditions
in Hamilton Harbour should not
limit natural reproduction and the
edibility of cold water species."
So - what are protection goals?
…….. a term which is inconsistently used!
But obviously need to know what you want to protect before
conducting an assessment/setting dose rate benchmarks
- what is protecting the environment? …. There appears to be no
internationally agreed definition.
How are protection goals being defined in radiological
protection/what’s driving the need for assessment ?
Typical radiological
protection goal definition

For instance (from EC PROTECT project):

To protect the sustainability of populations of the
vast majority of all species and thus ensure
ecosystem function now and in the future.
Special attention should be given to keystone,
sentinel, rare, protected or culturally significant
species
Stakeholder involvement:
what do we mean by stakeholders?

Term stakeholders here means:


any person or organisation that could either be
affected by, or interested in, the outcome of a
decision
Consequently
Will vary with the objective of the assessment
 May include a wide range of people (experts, lay
people, elected people, volunteers, etc)

What is Problem Formulation?

Identifies the:
source (of radionuclides)
 receiving media
 any key receptor species
 assessment criteria to use
 uncertainties (either knowledge or data)


Considers the
need for, and takes into account, stakeholder
involvement
 legislation and/or any regulatory requirements

Problem formulation...

Should be documented


Commonly, by conceptual model


in a transparent & understandable way
describing what is known about the site
Level of detail required

will be influenced by a number of factors
Elements of assessment
Release
Dispersion model
Media concentration
Transfer model
Wholebody activity
concentrations
Dosimetry model
(external exposure)
Dose rate
Effects understanding/
numerical benchmark
Tier 1
Risk
www.ceh.ac.uk/PROTECT
Dosimetry model
(internal exposure)
Tier 1 – a simplified screening
tier



Designed to be simple and conservative
 User only needs to input media activity concentrations
Aims to identify sites of negligible concern, removed from further
assessment – with a high degree of confidence
Envisaged that most sites will only need this level of assessment
[i.e. ‘be screened out’]
Dose rate screening value
Dose rate below which it is agreed (for the
purposes of an assessment) that there is no
requirement for further evaluation
 In ERICA Tier 1 input media (soil, water,
sediment) activity concentrations are
compared to precalculated concentrations
estimated to give rise to the screening dose
rate for the most exposed organism


These are termed ‘Environmental Media
Concentration Limits’ (EMCL)
www.ceh.ac.uk/PROTECT
Required inputs – Tier 1

Maximum measured or
modelled media
concentrations



Terrestrial ecosystem - soil
(or air for a few
radionuclides)
Aquatic ecosystems – water
and/or sediment
If no measurements but
site release estimates then
Tool has simple dispersion
models
www.ceh.ac.uk/PROTECT
Reference organism?

Vast number of potential
organisms to simplify a set of
organisms have been selected
to represent different tropic
levels, organisms likely to be
exposed, radiosensitive
organisms, encompass all
European protected species,
incorporate ICRP RAPs


These are the ‘Reference
Organisms’
12 freshwater, 13 terrestrial,13
marine organisms
www.ceh.ac.uk/PROTECT
Terrestrial
Amphibian
Bird
Bird egg
Detritivorous invertebrate
Flying insects
Gastropod
Grasses and herbs
Lichen and bryophytes
Mammal
Reptile
Shrub
Soil invertebrate
Tree
Risk Quotient (RQ)
Sum of RQs adds together the RQs for the
radionuclides (may be for different organisms)
If RQ>1 then screening dose rate exceeded (under
these conservative assumptions)
www.ceh.ac.uk/PROTECT
Tier 2 – create organism

Common Lizard characteristics:

Size (cm) - 14 length x 1 width x 2 depth
Weight - 10 g
Occupancy - 50% in soil/50% on soil
Elements of assessment
Release
Dispersion model
Media concentration
Transfer model
Wholebody activity
concentrations
Dosimetry model
(external exposure)
Dose rate
Dosimetry model
(internal exposure)
Effects understanding/
numerical benchmark
Risk
www.ceh.ac.uk/PROTECT
Transfer model
Very simple:
Activity concentration in biota wholebody(Bq kg -1 fresh weight)
CR 
Activity concentration media(filtered water (Bq l -1 ), soil (Bq kg -1 dry weight) or air (Bq m -3 ))
Default values derived from literature review
Assumptions (‘extrapolation’) made where no
data
Activity concentration in sediment(Bq kg -1 dry weight)
K d (l kg ) 
Activity concentration in filtered water (Bq l -1 )
-1
www.ceh.ac.uk/PROTECT
RQ at Tier 2
www.ceh.ac.uk/PROTECT
Tier 3 distribution
Assume lognormal for all
 Soil

Am-241 300±50 Bq/kg
 Cs-137 9500±5000 Bq/kg


Deer
Am-241 1±0.5 Bq/kg
 Cs-137 5000±400 Bq/kg

www.ceh.ac.uk/PROTECT