centre for ecology & hydrology - lancaster october 2011 david copplestone & nick beresford

Introduction to the ERICA Tool

Centre for Ecology & Hydrology - Lancaster October 2011

David Copplestone & Nick Beresford

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

http://www.erica-tool.com/

http://www.project.facilia.se/erica/download.html

https://wiki.ceh.ac.uk/display/rpemain/ERICA+reports

www.ceh.ac.uk/PROTECT

ERICA flow chart

ERICA Integrated Approach

Concentration screening value

Dose rate screening value

Detailed analysis and evaluation of data. Interaction and supplementation with all relevant databases

Extrapolation (e.g. population, ecosystem)

Management Assessment Tool CharacterisationManagement Assessment Tool Characterisation

Tier 3

Site-specific

Probabilistic analysis

Tier 2

Tier 1

Sta

keho

lder

Invo

lvem

ent

Issues

and

options

Plan

Evaluation of assessment

April 2006

Problem formulation

Exit

Exit


Elements of assessment

Media concentration

Release

Dose rate

Risk

Dispersion model

Transfer model

Dosimetry model(internal exposure)

Wholebody activity concentrationsDosimetry model

(external exposure)

Effects understanding/ numerical benchmark

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?

GOAL

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 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

in a transparent & understandable way

Commonly, by conceptual model describing what is known about the site

Level of detail required will be influenced by a number of factors



Media concentration

Release

Dose rate

Risk

Dispersion model

Transfer model



(external exposure)

Effects understanding/ numerical benchmarkTier 1

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)


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


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

TerrestrialAmphibian Bird Bird egg Detritivorous invertebrateFlying insects GastropodGrasses and herbs Lichen and bryophytesMammal ReptileShrubSoil invertebrateTree


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)

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



Media concentration

Release

Dose rate

Risk

Dispersion model

Transfer model



(external exposure)

Effects understanding/ numerical benchmark


Transfer model

Very simple:

Default values derived from literature review

Assumptions (‘extrapolation’) made where no data

))m (Bq air or )dry weight kg (Bq soil),l (Bq water(filtered media ionconcentratActivity

weight)fresh kg (Bqbody wholebiota in ionconcentratActivity CR

3-1-1-

-1

)l (Bq waterfiltered in ionconcentratActivity

)dry weight kg (Bq sedimentin ionconcentratActivity )kg (l K

1-

-11-

d


RQ at Tier 2


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


Rules for estimating organism activity concentrations - aquatic ecosystems

Input water and sediment concentrations Biota concentration estimated as water conc. x CR Sediment used in external dose calculation

.... But if do not have water concentrations – what then? Water concentrations estimated as biota conc./CR

and/or sediment conc./Kd Missing biota and/or sediment concs then estimated

using predicted water concs and CRs & Kd respectively


Rules used in Tier 2 [new!] Freshwater ecosystem Select Pu-240 & all organisms No water data but have sediment (n=20),

fish (n=50) & amphibian (n=25) activity concentrations

Sediment 8000 Bq/kg DM (70% DM content) Fish 1E-1 Bq/kg FW Amphibian 1E-3 Bq/kg (FW)

centre for ecology & hydrology - lancaster october 2011 david copplestone & nick beresford

Documents

numerical benchmark

warm water species

water use goal

conceptual model

water quality

significant species

erica tool http

lay people