Brenda Howard (CEH) Outline Historical perspective – previous ICRP guidance Why this has changed - prime motivations International initiatives at the EC, IAEA, ICRP.
Download ReportTranscript Brenda Howard (CEH) Outline Historical perspective – previous ICRP guidance Why this has changed - prime motivations International initiatives at the EC, IAEA, ICRP.
Brenda Howard (CEH) 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 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) 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 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 www.ceh.ac.uk/PROTECT Interaction between key international bodies UNSCEAR Member States www.ceh.ac.uk/PROTECT ICRP EU Radiation Protection and Environment: development ICRP 1977, 1990 Recommendations UNSCEAR (1996) Scientific base Development of frameworks IAEA 2005 Report on Effects of Ionizing Radiation to Biota USA, Canadian, EU-Projects (2000-2009) 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) 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 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” www.ceh.ac.uk/PROTECT 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 www.ceh.ac.uk/PROTECT 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 Protection targets Maintain biological diversity Conservation of species Protect health and status of 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 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 www.ceh.ac.uk/PROTECT 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. 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.” www.ceh.ac.uk/PROTECT 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 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 www.ceh.ac.uk/PROTECT UNSCEAR 1996 Acute doses 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 www.ceh.ac.uk/PROTECT 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 ”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 www.ceh.ac.uk/PROTECT 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) Graded approach for the REIA Endpoints Models and methods 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 EC Euratom Basic Safety Standards CURRENT New BSS outline DRAFT Title X: Protection of the Environment only Euratom projects FASSET ERICA PROTECT FP7 – STAR Network 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 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 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 www.ceh.ac.uk/PROTECT 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 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 www.ceh.ac.uk/PROTECT 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? 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 www.ceh.ac.uk/PROTECT Assessment Tools 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 RESRAD-BIOTA and R&D 128 mentioned when they have features not present in ERICA Tool www.ceh.ac.uk/PROTECT