Transcript Radiation protection

Centre for Ecology & Hydrology - Lancaster
1st – 3rd April 2014
Outline
Historical perspective of environmental
radiological protection
 Why this has changed - prime motivations
 International initiatives in key international
bodies
 The UK perspective
 Comparison with chemicals
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The ICRP statements
‘Although the principal objective of radiation
protection is the achievement and maintenance of
appropriately safe conditions for activities involving
human exposure, the level of safety required for the
protection of all human individuals is thought likely to
be adequate to protect other species, although not
necessarily individual members of those species.
The Commission therefore believes that if man is
adequately protected then other living things are
also likely to be sufficiently protected.’
ICRP, 1977
The ICRP statements
“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.
ICRP, 1991
Whats the issue?
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Human radiological protection:
Focus on worker/most exposed
individual
 Environment more as a route for
transfer to humans
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Incomplete ecological information
 What’s the protection goal?
 Evidence needed for or against
ICRP statement
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Challenges to anthropogenic
approach
Lack of demonstration that the
environment is being protected
 May not be valid for some environments
(e.g. those with no humans)
 Incompatible with management of other
environmental chemical stressors
 Requirement for assessment under
some national legislation
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Interaction between key
international bodies
UNSCEAR
evidence provision
ICRP
recommendations
establishing standards
Member
States
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EU
Chronology
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ICRP 1977 – statement appears
ICRP 1991 – recognise individuals may be impacted
ICRP 2007 – Recommendations include need to consider
environment and introduces ‘RAP Framework’
UNSCEAR (1996, 2011)
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USA, Canadian, EU-Projects (2000-2009)
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Scientific basis developed
Development of frameworks
IAEA (2005)
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Reports on Effects of Ionizing Radiation to Biota
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”
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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 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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Natural habitats
Communities
Ecosystems
Living organisms
Populations or higher organisational levels
Not on individuals (except for endangered species)
Demonstration through a set of Reference Animals and Plants (RAPs)
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Planned, Existing and Emergency exposure situations
Environmental radionuclide concentrations
Reference Male & Female
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 using representative individuals and
representative organisms
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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
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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
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Application of a
weighting factors for
RBE & different
tissues
ICRP 108 - RAPs
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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RAPs
•Considers 12 RAPs (adult life stages) and 39 elements
•RAPs defined at taxonomic level of Family
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Recent/ongoing ICRP work
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ICRP, 2003. A Framework for Assessing the Impact of
Ionising Radiation on Non-human Species. ICRP
Publication 91. Ann. ICRP 33 (3).
ICRP, 2008. Environmental Protection - the Concept
and Use of Reference Animals and Plants. ICRP
Publication 108. Ann. ICRP 38 (4-6).
ICRP, 2009. Environmental Protection: Transfer
Parameters for Reference Animals and Plants. ICRP
Publication 114. Ann. ICRP 39 (6).
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Ongoing ICRP focus
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Task groups on
Relative Biological Effectiveness
 More realistic dosimetry for non-human species
 Integrating the ICRP System of Protection for
humans and non-human species
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Forthcoming reports
The ICRP's approach to protection of the
environment under different exposure situations
 The Practical Application of Reference Animals
and Plants to Different Exposure Situations
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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
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UNSCEAR 2011 conclusions
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As in its 1996
recommendations, UNSCEAR
considers that chronic dose
rates of
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less than 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
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UNSCEAR 2011 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)
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Plan of Activities on Protection of the Environment 2005
IAEA Safety Fundamentals (2006)
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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
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Safety objective is:
“The fundamental safety
objective is to protect
people and the
environment from harmful
effects of ionizing
radiation”
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IAEA Fundamental Safety
Principles
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Principle 7 Protection of present and future
generations
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People and the environment, present and future,
must be protected against radiation risks
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Environment = Ecosystems and populations
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Basic Safety Standards
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Objectives
 Prevention of radiological effects
on flora and fauna
 Man is an integral part of the
environment
 Ensure the sustainable use of
natural resources now and in the
future
 Agriculture
 Forestry
 Fisheries
 Tourism
Basic Safety Standards
Requirements
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Consider Protection of the Environment
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Registration and licensing
Setting discharge limits
Monitoring
Remediation
Protection of the environment is one factor during
optimization in existing and emergency exposure
situations
Associated Safety Guides and Safety Report under
development
=>
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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 from 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 installations
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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on 29 September 2011 the European Commission
adopted the Proposal for a Council Directive laying
down basic safety standards for protection against the
dangers arising from exposure to ionising radiation
[COM(2011)593].
Euratom projects
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FASSET
ERICA
PROTECT
FP7 – STAR Network
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Other 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 Directive in the
UK.
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The UK has interpreted the
EC Birds & Habitats
Directives as requiring
assessments to determine
that no authorised
discharges of radioactivity
will impact upon protected
(Natura 2000) sites.
USDOE
US DOE facilities are required to demonstrate annually that routine
radioactive release from their sites are protective of non-human
receptors
DOE Order 5400.5: In addition to providing protection to members
of the public, it is DOE’s objective to protect the environment from
radioactive contamination to the extent practical.
Assessed against dose rate limits for different organism groups
established to avoid measurable impairment of reproductive
capacity
Objective: to protect the terrestrial and aquatic environment,
including populations of animals and plants within and beyond the
boundaries of DOE sites ……
Differences between chemical and
radiological risk assessments
Exposure
Assessment
Chemical approaches often consider factors that affect
bioavailability
Dosimetry
Needed for
assessments.
radionuclide
but
not
chemical
risk
Possible internal and external exposure from radionuclides
but only internal relevant for chemicals
Effects
Assessment
Assessment of chemicals is based on empirical
ecotoxicological data relating concentrations or daily
intakes to effects
Assessment of radionuclides uses data that relate effects to
dose.
Separate assessments are needed for each chemical
Radionuclide assessments need only consider a limited
range of radiation types and qualities
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Soil bioavailability
M input
g ha-1 a-1
Soil solids
Soil water
H+
Maq
M-soil
Mz+
M-X
M-DOM
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M output = [M]aq x runoff
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
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Some examples of assessments
being conducted
Sweden, UK, Canada & Finland – waste
repositories
 England & Wales >700 authorisations
impacting on (protected) Natura 2000 sites
 USDOE sites – assessment is an annual
requirement
 U industry – (e.g. Canada, Australia)
 New build power plants (e.g. UK)
 Decommissioning (e.g. Lithuania)
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