Radiation protection of the environment – an introduction
Brenda Howard (CEH)
www.ceh.ac.uk/PROTECT
Outline 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
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)
History
Focus on worker/most exposed individuals Incomplete ecological information Limited evidence provided to support
statement Changing attitudes
Late 1990s tools and techniques available Recognition of environmental risks (e.g. Rio) Conservation and protection drivers
History
Focus on worker/most exposed individuals Incomplete ecological information No evidence provided to support statement Changing attitudes
Late 1990s tools and techniques available Recognition of environmental risks (e.g. Rio) Conservation and protection drivers
The need to explicitly demonstra
te no impact…
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Drivers
National legislation National interpretation of international
legislation Various bodies – need to explicitly
demonstrate/why different to chemicals 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
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Interaction between key international bodies
IAEA
ICRPUNSCEAR
Member States
EU
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Radiation Protection and Environment: development
ICRP 1977, 1990 Recommendations If there is compliance with radiation protection standards for
man, other species are not put at risk UNSCEAR (1996)
Report on Effects of Ionizing Radiation to Biota USA, Canadian, EU-Projects (2000-2009)
Scientific base Development of frameworks
IAEA 2005 Setup of the ”Plan of Activities on Protection of the
Environment”
IAEA Safety Fundamentals (2006) Principle 7:Protection of “People and the environment, present
and in the future, must be protected against radiation risks”
ICRP 2007 (Publication 103) Recommendations - the Environment
Recommends the explicit consideration of
Radiological Protection of the Environment
ICRP recognised 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
Assess exposure – dose – effect relationships Pragmatic approach No “dose limits”
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ICRP Exposure Situations
Planned - 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
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 Used in USA for previously contaminated sites
Emergency – eg accidents, malevolent acts Low priority in acute phase
ICRP Publication 108 (2008)
Provides a Concept and Use of Reference Animals and Plants Transfer, Dosimetry, Effects to biota
=> Derived Consideration Reference Levels Ideas for application
Maintain biological diversity Conservation of species Protect health and status of
Natural habitats Communities Ecosystems
Targets are all related to Living organisms Populations or higher organisational levels Not on individuals (except for endangered species)
Protection of natural resources not included Soil, water, air
Demonstration through a set of Reference Animals and Plants (RAPs)
Protection targets
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Planned, Existing and Emergency exposure situations
Environmental radionuclide concentrations
Reference Male & FemaleReference Person
Dose limits, Constraints and Reference levels
Reference Animals and Plants
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
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Human assessment (overview)
RADIONUCLIDE SOURCE
HABITS DATA
REFERENCE PERSON
IMPACT
TOTAL ABSORBED
DOSE
PATHWAY OF EXPOSURE
Application of a weighting factors
for RBE & different tissues
Compare predicted dose to known biological effects & dose limits
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Wildlife assessment (overview)
RADIONUCLIDE SOURCE
HABITS DATA
REFERENCE ANIMAL OR
PLANT
IMPACT
TOTAL ABSORBED
DOSE
PATHWAY OF EXPOSURE
Application of a weighting factors
for RBE & different tissues
Compare predicted dose to known biological or
ecological effects & guideline values
ECOLOGICAL PARAMETERS
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RAPs
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RAP definitionFor 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.
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: “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
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UNSCEAR - environment
Report on “Effects of radiation on the Environment” in 1996
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
UNSCEAR 1996
Acute doses
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UNSCEAR draft conclusions
As in its 1996 recommendations, UNSCEAR considers that chronic dose rates of
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
Category Dose rate Effects Endpoint
Plant
100 - 1000 μGy h-1 Reduced trunk growth of pine trees Morbidity
400 -700 μGy h-1 Reduced numbers of herbaceous plants Morbidity
Fish
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
Mammals< 100 μGy h-1 No detrimental endpoints have been described Morbidity,
Mortality,Reproductive
Generic ecosystems
(terrestrial and aquatic)
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
Overall summary of (illustrative) chronic effects data for plants, fish and mammals
UNSCEAR draft conclusions
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”Plan of Activities on Protection of the
Environment” 2005 After Stockholm conference in 2003
IAEA Safety Fundamentals (2006) Principle 7:Protection of “People and the
environment, present and in the future, must
be protected against radiation risks”
Biota Co-ordination Group
Revision of Basic Safety Standards
Approaches Environmental Modelling for Radiation Safety
Application Technical cooperation on wildlife regulation
RER 7005
Revision of the International Basic Safety Standards (BSS), Draft 4.0,
September 2010 Introduction
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 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
Radiological Environmental Impact Analysis for Facilities and Activities
(REIA) (New Safety Guide) How to perform a Radiological Environmental Impact Assessment
(REIA) Endpoints Models and methods
Graded approach for the REIA Which efforts are needed for
Small users Hospitals Nuclear installation
How to use already existing data for REIA 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) 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
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EC Euratom Basic Safety Standards
New BSS outline Title X: Protection of the Environment
Euratom projects FASSET ERICA PROTECT FP7 – STAR Network
CURRENT DRAFT only
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 103Member 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 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 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
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EC Drivers in the UK Europe: Habitats and Birds
Directives On the conservation of natural
habitats and of wild flora and fauna
UK: Conservation (Natural Habitats) regulations 1994 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
Tiered Assessments
Many approaches use a tiered assessment structure (in common with other areas of risk assessments) simple initial screening through to more refined
assessments Also referred to as:
staged or graded approaches
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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
Tiered approach
Environmental and health protection
Conservatism
Resources
TIER 1Risk screening
TIER 2Generic quantitative
TIER 3Detailed Quantitative
Data needs
Tiered approach
Environmental and health protection
Conservatism
Resources
TIER 1Risk screening
TIER 2Generic quantitative
TIER 3Detailed Quantitative
Data needs
The level of detail in a ris
k assessment should be proportionate
with the nature and complexity of the ris
k being addressed and
consistent with decision-m
aking needs
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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
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
Approaches for chemicals in the environment
Soil solids Soil water
M-DOM
M-X
M-soil
M output = [M]aq x runoff
M inputg ha-1 a-1
H+
Mz+
Maq
Soil bioavailability
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)
Critical Loads for LeadLead
0 - 200
200 - 400
400 - 800
>800
Lead
0 - 200
200 - 400
400 - 800
>800
0 - 200
200 - 400
400 - 800
>800
no exceedance
0 - 10
1 - 20
>20
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)
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Why are we giving these courses?
Assessments are being done – little formal training available - 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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Assessment Tools Three tools freely available and usable by others Focus here on ERICA Tool developed by EC
consortium
RESRAD-BIOTA and R&D 128 mentioned when they have features not present in ERICA Tool
EPICFP4
FASSETFP4
ERICAFP5
PROTECTFP6