Transcript Radiological protection of the environment

Brenda Howard (CEH)
Outline
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Historical perspective – previous ICRP guidance
Why this has changed - prime motivations
International initiatives at the EC, IAEA, ICRP and
UNSCEAR
Comparison with system for humans
The situations in which assessments may be used
Radiation protection of the environment in the UK
Tiered assessments
Comparison with chemicals
The course
www.ceh.ac.uk/PROTECT
Historical perspective – previous ICRP
guidance
“The
Commission believes that the standard of
environmental control needed to protect man to the
degree currently thought desirable will ensure that
other species are not put at risk. Occasionally,
individual members of non-human species might be
harmed, but not to the extent of endangering whole
species or creating imbalance between species. At the
present time, the Commission concerns itself with
mankind’s environment only with regard to the transfer
of radionuclides through the environment, since this
directly affects the radiological protection of man”
ICRP, 1991, Para. 16
History
Focus on worker/most exposed individuals
 Incomplete ecological information
 Limited evidence provided to support
statement (in the context of the environment)
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History
Focus on worker/most exposed individuals
 Incomplete ecological information
 Limited evidence provided to support
statement
 Changing attitudes
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Late 1990s tools and techniques available
 Recognition of environmental risks (e.g. Rio)
 Conservation and protection drivers
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History
Focus on worker/most exposed individuals
 Incomplete ecological information
 No evidence provided to support statement
 Changing attitudes
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Late 1990s tools and techniques available
 Recognition of environmental risks (e.g. Rio)
 Conservation and protection drivers
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Drivers
National legislation
 National interpretation of international
legislation
 Various bodies – need to explicitly
demonstrate/why different to chemicals
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IUR promoted need for an approach not
based on humans
OECD-NEA has highlighted the need for
radiological assessment of non-human
biota and supported tiered assessment
approach
www.ceh.ac.uk/PROTECT
Interaction between key
international bodies
UNSCEAR
Member
States
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ICRP
EU
Radiation Protection and
Environment: development
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ICRP 1977, 1990 Recommendations
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UNSCEAR (1996)
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Scientific base
Development of frameworks
IAEA 2005
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Report on Effects of Ionizing Radiation to Biota
USA, Canadian, EU-Projects (2000-2009)
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If there is compliance with radiation protection standards for
man, other species are not put at risk
Setup of the ”Plan of Activities on Protection of the
Environment”
IAEA Safety Fundamentals (2006)
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Principle 7:Protection of “People and the environment,
present and in the future, must be protected against radiation
risks”
www.ceh.ac.uk/PROTECT
ICRP 2007 (Publication 103)
Recommendations - the Environment
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Recommends the explicit consideration of
Radiological Protection of the Environment
ICRP recognised
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Need for advice and guidance
Lack of consistency at an international level
More proactive approach needed
Complex nature of environmental protection
Need to develop a clearer framework – C5
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Assess exposure – dose – effect relationships
Pragmatic approach
No “dose limits”
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ICRP Exposure Situations
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Planned
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- current activities, new nuclear sites and U mines etc
Not historic (yrs of discharge)
Mostly for planned NPP and waste repositories (current or
prospective discharges)
 Existing – exposure to natural radiation sources and contamination
of areas by residual radioactive material
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Past activities that were never subject to regulatory control or were not
regulated according to present requirements;
An emergency, after the emergency exposure situation has been
declared ended
Residues from past activities for which there is no longer legally
accountability
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Used in USA for previously contaminated sites
Emergency – eg accidents, malevolent acts
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Low priority in acute phase
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ICRP Publication 108 (2008)
Provides a Concept and Use of Reference Animals and Plants
 Transfer, Dosimetry, Effects to biota
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=> Derived Consideration Reference Levels
Ideas for application
Protection targets
 Maintain biological diversity
 Conservation of species
 Protect health and status of
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Targets are all related to
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Living organisms
Populations or higher organisational levels
Not on individuals (except for endangered species)
Protection of natural resources not included
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Natural habitats
Communities
Ecosystems
Soil, water, air
Demonstration through a set of Reference Animals and Plants (RAPs)
www.ceh.ac.uk/PROTECT
Planned, Existing and Emergency exposure situations
Environmental radionuclide concentrations
Reference Male & Female
Reference Person
Reference Animals and Plants
Dose limits, Constraints and
Reference levels
Derived Consideration
Reference Levels
Decision-making regarding public health and environmental protection for the
same environmental exposure situation by way of representative individuals and
representative organisms
www.ceh.ac.uk/PROTECT
Human assessment (overview)
RADIONUCLIDE
SOURCE
PATHWAY OF
EXPOSURE
HABITS DATA
REFERENCE
PERSON
TOTAL
ABSORBED
DOSE
Compare predicted dose to
known biological effects &
dose limits
IMPACT
www.ceh.ac.uk/PROTECT
Application of a
weighting factors for
RBE & different
tissues
Wildlife assessment (overview)
RADIONUCLIDE
SOURCE
PATHWAY OF
EXPOSURE
ECOLOGICAL
HABITS
DATA
PARAMETERS
REFERENCE
ANIMAL OR
PLANT
Compare predicted dose to
known biological or
ecological effects & guideline
values
TOTAL
ABSORBED
DOSE
IMPACT
www.ceh.ac.uk/PROTECT
Application of a
weighting factors for
RBE & different
tissues
RAPs
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RAP definition
For human protection, the reference individuals and Reference Person are
idealised models developed for the specific purposes of relating
exposure to dose, and dose to effect.
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They do not represent any specific type of human being (the reference
individuals are phantoms, and the Reference Person is a
hermaphrodite), but nevertheless have to be discretely defined to serve
their basic purpose.
To be consistent with the original concept of Reference Man, a Reference
Animal or Plant can be described as follows:
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“A Reference Animal or Plant is a hypothetical entity, with the assumed
basic biological characteristics of a particular type of animal or plant, as
described to the generality of the taxonomic level of family, with 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.”
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UNSCEAR
United Nations Scientific Committee on the Effects of
Atomic Radiation
 Established in 1955
 UN Scientific Committee reports to General
Assembly
 Assesses global levels and effects of ionizing
radiation
 Provides scientific basis for radiation protection
 Governments and organisations rely on Committee's
estimates as the scientific basis for evaluating
radiation risk and establishing protective measures
www.ceh.ac.uk/PROTECT
UNSCEAR - environment
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Report on “Effects of radiation on the
Environment” in 1996
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Limited available data
Review of data, including Chernobyl
Based largely on acute data
Effects difficult to estimate due to long term
recovery, compensatory behaviour and
confounding environmental factors
New report imminent
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UNSCEAR 1996
Acute doses
UNSCEAR draft conclusions
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As in its 1996 recommendations, UNSCEAR
considers that chronic dose rates of
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less than (about) 100 μGy h-1 to the most highly
exposed individuals would be unlikely to have
significant effects on most terrestrial communities; and
that maximum dose rates of 400 μGy h-1 to any
individual in aquatic populations of organisms would be
unlikely to have any detrimental effect at the population
level
nominal Relative Biological Effectiveness
(RBEs) of 10 for internally deposited alpha
radiation and 1 for beta radiation were
recommended
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UNSCEAR draft conclusions
Overall summary of (illustrative) chronic effects data for plants, fish and mammals
Category
Plant
Dose rate
Effects
Endpoint
100 - 1000 μGy h-1
Reduced trunk growth of pine trees
Morbidity
400 -700 μGy h-1
Reduced numbers of herbaceous plants
Morbidity
100 -1000 μGy h-1
Reduction in testis mass and sperm production,
lower fecundity, delayed spawning
Reproductive
200 – 499 μGy h-1
Reduced spermatogonia and sperm in tissues
Reproductive
< 100 μGy h-1
No detrimental endpoints have been described
Morbidity,
Mortality,
Reproductive
About 80 μGy h-1
A new statistical approach (species sensitivity
distribution, SSD) was applied to radiation
effects data to estimate the hazardous dose rate
(HDR5), the dose rate at which 95% of the
species in the ecosystem are protected
Morbidity,
Mortality,
Reproductive
Fish
Mammals
Generic
ecosystems
(terrestrial and
aquatic)
www.ceh.ac.uk/PROTECT
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”Plan of Activities on Protection of the
Environment” 2005
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After Stockholm conference in 2003
IAEA Safety Fundamentals (2006)
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Principle 7:Protection of “People and the
environment, present and in the future, must
be protected against radiation risks”
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Biota Co-ordination Group
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Revision of Basic Safety Standards
Approaches
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Environmental Modelling for Radiation Safety
Application
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Technical cooperation on wildlife regulation
RER 7005
www.ceh.ac.uk/PROTECT
Revision of the International Basic
Safety Standards (BSS), Draft 4.0,
September 2010
Introduction
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Protection of people and the environment
 Prevention of radiological effects on human health and on flora and
fauna.
 Adopt an integrated perspective to ensure the sustainable use of
natural resources for agriculture, forestry, fisheries and tourism - now
and in the future.
Requirements
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=>
Consider Protection of the Environment
 Registration and licensing
 Setting discharge limits
 Protection of the environment is one factor during optimization in
existing and emergency exposure situations
3 Safety Guides and 1 Safety Report under development
Radiation Protection of the Public and
the Environment (New Safety Guide)
Guidance for the implementation of radiation protection as
recommended in the new BSS
 Exposures to public
 Exposures to environment
 How to apply radiation protection principles to exposures of
the environment
 Justification, Limitation, Optimization
 Exposure situations
 Planned, existing, emergency
 Discuss the application of Derived Consideration Reference
Levels
=> Input expected from a currently working ICRP Task Group
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Radiological Environmental Impact
Analysis for Facilities and Activities
(REIA) (New Safety Guide)
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How to perform a Radiological Environmental Impact
Assessment (REIA)
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Graded approach for the REIA
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Endpoints
Models and methods
Which efforts are needed for
 Small users
 Hospitals
 Nuclear installation
How to use already existing data for REIA
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Data used for assessment of exposures to the public
Results from environmental and source monitoring
=> Minimize efforts needed for assessing impacts to biota
Regulatory Control of the Releases of
Radioactive Material (Update of a
Safety Guide)
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Guidance to derive limits for radionuclide discharges to the
environment
 Public exposure
 Environmental exposure
Facilities and activities
 Nuclear installations
 Laboratories and hospitals
 Small users
 NORM
=>Radiological impact to biota will be an integral part of the
licensing process
EC
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Euratom Basic Safety Standards
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CURRENT
New BSS
outline
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DRAFT
Title X: Protection
of the Environment
only
Euratom projects
FASSET
 ERICA
 PROTECT
 FP7 – STAR Network
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www.ceh.ac.uk/PROTECT
Title X: Protection of the Environment
Article 102
Member States shall include, in the legal framework for
radiation protection, provision for the radiation protection of
non-human species in the environment; this legal
framework shall introduce environmental criteria aiming at
the protection of populations of vulnerable or representative
non-human species with regard to their significance as part
of the ecosystem. Where appropriate, practices shall be
identified for which regulatory control is warranted to
implement the requirements in this legal framework and
take account of appropriate environmental assessment
criteria
Title X: Protection of the Environment
Article 103
Member States' competent authorities, when establishing authorised limits
on discharges of radioactive effluents, in accordance with Article 91
paragraph 2, shall also ensure adequate protection of non-human
species; for this purpose a generic screening assessment may be
conducted to provide reliance that the environmental criteria are met.
Article 104
Member States shall require undertakings to take appropriate technical
measures with the aim to avoid that in the event of an accidental
release there will be significant environmental damage, or to mitigate
the extent of such consequences.
Article 105
While establishing environmental monitoring programmes, or
requiring such programmes to be carried out, Member States'
competent authorities shall include representative nonhuman species, if
necessary, in addition to such environmental media which constitute a
pathway of exposure to members of the public.
Article 31 Group of Experts
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Recognise that
 in line with ICRP Publication 103, is a need for specific
consideration of the exposure of biota where appropriate
 environmental criteria as well as dose constraints should
be considered for the authorisation of discharges of
radioactive effluent
Support the development of a framework by ICRP C5
Article 31 Group of Experts
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Recognise that
 in line with ICRP Publication 103, is a need for specific
consideration of the exposure of biota where appropriate
 environmental criteria as well as dose constraints should
be considered for the authorisation of discharges of
radioactive effluent
Support the development of RAPS and framework
But feel that protection of the environment should not
warrant a high level of regulatory control with demonstration
of compliance proportionate to risk and allow enough time
for transposition into national law
EC Drivers in the UK
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Europe: Habitats and Birds
Directives
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On the conservation of natural
habitats and of wild flora and
fauna
UK: Conservation (Natural
Habitats) regulations 1994
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Implements the Habitats
Directive in the UK. Requires
steps to maintain and restoration
to favourable conservation
status of habitats and species of
Community level interest
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Tiered Assessments
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Many approaches use a tiered assessment
structure (in common with other areas of risk
assessments)
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simple initial screening through to more refined
assessments
Also referred to as:
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staged or graded approaches
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
Tiered approach
TIER 1
TIER 2
TIER 3
Risk screening
Generic quantitative
Detailed Quantitative
Environmental and health protection
Data needs
Conservatism
Resources
Tiered approach
TIER 1
TIER 2
TIER 3
Risk screening
Generic quantitative
Detailed Quantitative
Environmental and health protection
Data needs
Conservatism
Resources
Similarities and differences between
chemical and radiological risk assessments
Problem Formulation
Protection goals common to both approaches and risk assessments are
framed in this context.
Exposure Assessment
Environmental transfer of contaminants is a common feature but attention
to interactions between environment and orgamisms differs (chemical
approaches consider factors that affect bioavailability)
Dosimetry
A significant feature of radionuclide risk assessment but not chemical
assessments. Possible internal and external exposure from radionuclides
but only internal residues are relevant for chemicals
Effects Assessment
Significant differences: assessment of chemicals is based on empirical
ecotoxicological data relating concentrations or daily intakes to effects,
whilst assessment of radionuclides uses data that relate effects to dose.
Separate assessments are needed for each new chemical, but radionuclide
assessments need only consider a limited range of radiation types and
qualities
Risk characterisation
Similar approaches for characterising risk can be used for both chemicals
and radioactive substances
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Approaches for chemicals in the
environment
Direct toxicity in soil and water: the assessment of toxicity
thresholds for plants, invertebrates and microbial processes
Higher organism health: comparison with
•Concentration in food eaten
•Ingested amount per unit liveweight of receptor species
•Concentration in organs of species compared to a risk
quotient
Human health: quantifying exposure to contaminants and
assessing acceptable intake values
Soil bioavailability
M input
g ha-1 a-1
Soil solids
Soil water
H+
Maq
M-soil
Mz+
M-X
M-DOM
M output = [M]aq x runoff
Critical Loads
The critical load is the rate of deposition of a
metal from the atmosphere, which at steady
state, leads to the metal concentration in
soils or water reaching a threshold for
adverse effects (the critical limit)
Lead
Critical Loads for Lead
0 - 200
200 - 400
400 - 800
>800
no exceedance
0 - 10
1 - 20
>20
Critical Load for Pb (g
ha-1
y-1)
Exceedance of Critical Load for Pb
in Managed Broadleaf Woodland
(ratio)
Why are we giving these
courses?
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Assessments are being done – little formal
training available
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- so we don't assume much prior knowledge
We are being asked for advice on use of
assessment tools
 The tools are only recently developed and
there are various complexities and
assumptions which need to be understood
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www.ceh.ac.uk/PROTECT
Assessment Tools
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Three tools freely available and usable by others
Focus here on ERICA Tool developed by EC
consortium
EPIC
FP4
ERICA
PROTECT
FP5
FP6
FASSET
FP4
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RESRAD-BIOTA and R&D 128 mentioned when they
have features not present in ERICA Tool
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