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Absorbed dose

Quantity of energy imparted by ionising radiation to unit mass of matter such as tissue. Unit gray, symbol Gy. 1 Gy = 1 joule per kilogram.

Activity Concentration

The activity per unit mass or volume, e.g. Bq kg-1, Bq l-1

AECL

Atomic Energy Canada Limited

ALARA

"As low as reasonably achievable", refers to actions directed to limiting doses to individuals, the number of exposed individuals, and the probability of receiving a dose.

Allometry

Relationships between body mass of organisms and various parameters (including of relevance to PROTECT radionuclide biological half-life and dietary dry matter intake).

Assessment Endpoint

The biological effect inferred from measurements or predictions and which the assessment framework is designed to study.

Assessment factor

Allowance for degree of uncertainty, caused by lack of effects data. For example, an estimated lowest observed effect concentration may, as a precautionary approach, be divided by a assessment factor (normally within the range of 10 to 10000) to safeguard against harmful effects, where the magnitude of the assessment factor reflects the degree and type of uncertainty (e.g. lack of chronic exposure data, lack of data for different taxonomic groups or trophic levels, etc.). The assessment factor (AF) is also know as the safety factor.

Assessment Framework

Identification and demarcation of the assessment boundaries. In FASSET, the framework contains the process from problem formulation through to characterisation of the effects of radiation on individuals. The overall
assessment system describes the tools, methods and information flow used to carry out the impact assessment.

Authorisation

he granting by a regulatory body or other governmental body of written permission for an operator to perform specified activities.

BAT

Best Available Technology: a term applied to abatement technology designed to limit pollutant discharges. The term constitutes a moving target on practices, since developing societal values and advancing techniques may change what is currently regarded as 'best available'. Similar terms include 'best practicable means' and 'best practicable environmental option'.

BCG

Biota Concentration Guidelines: the media concentration for which the corresponding dose rate is equal to the screening dose rate used in the USDoE's
graded approach and RESRAD-BIOTA assessment tool.

BCG calculator

Biota Concentration Guidelines calculator: A semi-automated tool for implementing screening and analysis methods contained within the USDoE graded approach. Although the BCG calculator is still available RESRAD-BIOTA has been developed to replace it.

Benchmark

Risk assessment benchmarks are the concentrations, doses or dose rates that are estimated to equate to predefined criteria (e.g. predicted no effects dose rate,
severe risk) based on exposure-response information and political/societal decisions.

Bioaccumulation

The process whereby an organism accumulates substances in living tissues to concentrations higher than those existing in the surrounding media.

Bioassay

A test to determine the relative strength of a substance by comparing its effect on a test organism with that of a standard preparation.

Bioavailability

Defined as the fraction of the contaminant that can be taken up by living organisms, dependant both on the chemical speciation of the exposure source(s) and on the physiological status of the organism.

Biodiversity

The number and abundance of species found within a common environment. This includes the variety of genes, species, ecosystems, and the ecological processes that connect everything in a common environment.

Biological half-life

The time required for a biological system (e.g. an animal) to eliminate, by natural processes, half the amount of a substance that has been absorbed into that system.

Biomagnification

Situations where the concentration of certain substances increases up the food chain.

Biosphere

That part of the environment normally inhabited by living organisms. In practice, the biosphere is not usually defined with great precision, but is generally taken to include the atmosphere and the Earth's surface, including the soil, surface water bodies, seas and oceans and their sediments. There is no generally accepted definition of the depth below the surface at which soil or sediment ceases to be part of the biosphere, but this might typically be taken to be the depth affected by basic human actions, particularly farming. In waste safety in particular, the biosphere is normally distinguished from the geosphere.

Birds Directive

The abbreviated term of 'Council Directive 79/409/EEC of 2 April 1979 on the Conservation of Wild Birds'. It is the aim of this directive to promote the
conservation and protection of listed species of birds within the European Union.

BPEO

Best Practicable Environmental Option, see BAT.

BPM

Best Practicable Means, see BAT.

BWG

Biota Working Group: Part of the IAEA EMRAS programme aimed at comparing and validating models used and developed by member states for biota dose assessments that may be used as part of a regulatory processes concerning authorised releases of radionuclides in order to improve Member States' capabilities for protection of the environment.

Conceptual model

Representation of the environmental system and of the physico-chemical and biological processes that determine the transport/transfer of contaminants from sources through environmental media to ecological receptors within the system.

Contaminant

Any physical, chemical, biological, or radiological substance or matter that has a potentially adverse effect on air, water, or soil, with the implication that the amount is measurable.

CR

Concentration ratio: ratio used to quantify the equilibrium between an environmental medium and a living organism (e.g., water to fish CR). Sometimes referred to as concentration factor or bioaccumulation factor.

Cytogenetic effect

An observed effect in chromosomes that can be correlated with adverse hereditary effects or genetic effects (effects that are inheritable and appear in the descendants of those exposed).

DCC

Dose Conversion Coefficient expressed as Gy per kg of the target organism per Bq per unit of mass or volume of the source. The DCC is specific to each radionuclide and organism and was calculated for external and internal
exposure. Sometimes referred to as the Dose Conversion Factor.

DCF

Dose Conversion Factor, see Dose Conversion Coefficient.

DCL

Derived consideration level: A band of absorbed dose rate for each Reference Animal and Plant within the ICRP proposed framework. These do not represent dose limits but a range of doses which form a starting point from which dose limits may be considered in the future.

Dispersion model

Model for the representation of the spreading of radionuclides in air (aerodynamic dispersion) or water (hydrodynamic dispersion) resulting mainly from physical processes affecting the velocity of different molecules in the medium.

Dose

See absorbed dose

Dose constraint

A restriction on annual dose to an individual (human), which may either relate to a single dose or to a complete site, in order to ensure that when aggregated with doses from all sources, excluding natural background and medical procedures, the dose limit is not exceeded.

Dose rate

Dose (normally absorbed dose) received over a specified unit of time.

Dose-effect

The relationship between dose (usually an estimate of dose) and the gradation of the effect in an exposed population, that is a biological change measured on a graded scale of severity.

Dose-response

A correlation between a quantified exposure (dose) and the proportion of an exposed population that demonstrates a specific effect (response).

Dosimetry

The measurement and calculation of radiation dose in matter and tissue resulting from exposure to ionising radiation.

DWB

Direct Weighted Bootstrap

EA R&D 128

Radiological assessment approach for wildlife and associated tool developed by the England and Wales Environment Agency.

Ecological impact

The total effect of an environmental change, natural or man-made, on the community of living organisms.

Ecological Receptor

Living organisms at various organisational levels (i.e. ecosystems, communities, populations, individual organisms) potentially exposed to and adversely affected by stressors because they are present in the source(s) and/or along stressor migration pathways. This term dose not refer to humans.

Ecosystem

The interacting system of a biological community and its nonliving surroundings.

ECx

Effect Concentration: the concentration of a chemical required to cause a given effect to x% of a population or community. For example, EC10: concentration of a chemical required to cause a given effect in 10% of a population or community.

EDRx

Effects Dose Rate: the radiation dose rate required to cause a given effect to x% of a population or community. For example, EDR10: the dose rate required to cause a given effect in 10% of a population or community. Effect A biological change caused by an exposure. Strictly speaking, an effect is the change in an endpoint under consideration when it is compared to a control.

EIA

Environmental Impact Assessment

EMRAS

Environmental Modelling for Radiation Safety: An IAEA programme aimed at improving models for the purposes of radiation protection of the public and the environment (

http://www-ns.iaea.org/projects/emras

).

EMCLS

Environmental Media Concentration Limits: Used as part of the ERICA Tool and defined as the activity concentration in the selected media (soil, air, water or sediment) that would result in a dose-rate to the most exposed reference organism equal to that of the selected screening dose-rate.

Endpoint

In toxicity testing and evaluation it is the biological response that is measured. Endpoints vary with the level of biological organisation being examined and include responses at the subcellular level to the community level such as biomarkers (subcellular level), survival, growth, reproduction (individual
level), primary production, and structure (and abundance) and function in a community (population or community level). Endpoints are used in toxicity tests as criteria for effects.

ENEV

Environmental No Effects Value: a dose level at which a population of organisms will not be affected (defined by Environment Canada).

Environment

Water, air, land, plants and man and all other organisms living therein, and the interrelationships which exist among them.

EIS

Environmental Impact Statement: a document providing information for decision makers on the positive and negative effects of an action, practice or policy, which identifies and evaluates the environmental impacts of the hazard source and feasible alternatives, including taking no action.

Environmental Justice

Often used interchangeably with the term environmental equity, refers to the distribution and effects of environmental problems and the policies and processes to reduce differences in who bears environmental risks. In a general sense, it includes concern for disproportionate risk burden placed upon any population group, as defined by gender, age, income, race, nationality or generation.