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Definitions of relevant terms and some commonly used abbreviations.

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Term

Meaning

A

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.

B

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.
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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.
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.
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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 Living organisms at various organisational levels (i.e. ecosystems, communities,
Receptor populations, individual organisms) potentially exposed to and adversely affected by
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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 Often used interchangeably with the term environmental equity, refers to the
Justice 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.
Environmental The levels of pollution and lengths of exposure, above which adverse effects
quality criteria may occur on health and welfare.
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Environmental The level of contaminants prescribed by law or regulation that cannot be
quality standards exceeded during a specified time in a defined area.
EQSs Environmental Quality Standards
ERA Ecological Risk Assessment
ERICA Environmental Risk from Ionising Contaminants: Assessment and
Management, EURATOM 6th Framework project (see www.erica-project.org).
ERICA Tool A tool implementing the ERICA tiered approach for radiological assessment of
wildlife in freshwater, terrestrial and marine ecosystems developed by an
EURATOM 6th Framework consortium.
Habitats Directive The abbreviated term of 'Council Directive 92/43/EEC of 21 May 1992 on the
conservation of Natural Habitats and the Wild Fauna and Flora'. It is the aim of this
directive to promote the conservation of certain habitats and species within the
European Union.
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.
EURATOM European Atomic Energy Community
Exposure The co-occurrence or contact between the endpoint organism and the stressor
(e.g. radiation or radionuclide).
Exposure The process of measuring or estimating the intensity, frequency, and duration
Assessment of exposures to an agent currently present in the environment or of estimating
hypothetical exposures that might arise from the release of new chemicals into
the environment.
Exposure pathway A route by which radiation or radionuclides can reach humans and cause
exposure - an exposure pathway may be very simple, e.g. external exposure
from airborne radionuclides, or a more complex chain.
FASSET Framework for Assessment of Environmental Impact EURATOM 5th Framework
project (see http://www.ceh.ac.uk/protect/FASSETdeliverables.html).
Feature species see reference organisms
Fecundity The number of viable offspring produced by an organism; mature seeds produced,
eggs laid, or live offspring delivered, excluding fertilised embryos that have failed to
develop.
Fertility The ability to produce offspring.
Foundation species Highly interactive species that are often extremely abundant or ecologically
dominant.
FREDERICA The FASSET Radiation Effects Database (FRED) which has been updated through
the addition of a quality scoring exercise of each literature source to evaluate how
useable the data is in the context of defining dose (rate) effect relationships for
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incorporation into the SSD and other approaches. In addition new literature
sources have been added to the database and it has been updated to make it
available on the internet. It has been renamed as the FREDERICA database in
recognition of these changes (www.frederica-online.org).
Gamma air kerma Gamma air kerma is exposure measured in air which is in effect, the absorbed dose
measured in air. See Kerma.
Hazard A condition or physical situation with a potential for an undesirable
consequence, such as harm to health or environment.
Hazard analysis Procedure used to (1) identify potential sources of release of hazardous
materials from fixed facilities or transportation accidents; (2) determine the
vulnerability of a geographical area to a release of hazardous materials; and (3)
compare hazards to determine which present greater or lesser risks to a
community.
Hazard Recognising that a hazard exists and trying to define its characteristics. The
Identification process of determining whether exposure to an agent can cause an increase in
the incidence of an adverse health or environmental effect.
HDRx Hazardous Dose (rate) affecting x% of the species of a given ecosystem. This
value is estimated from the Species Sensitivity Distribution.
HNED(R) The highest no effect dose or dose rate in a toxicity test that does not causes a
statistically significant effect in comparison to the control. The same definition
applies for Concentration. See NOEC.
Hormetic pattern Pattern of dose response where there is an initial 'positive' effect at low
concentrations of a chemical or low radiation dose rates, followed by a progressive
negative effect at higher concentrations or dose rates.
IAEA International Atomic Energy Agency, see www.iaea.org
ICRP International Commission on Radiological Protection, see www.icrp.org
Kd Distribution Coefficient used to quantify the equilibrium between solid and
liquid phases (soil or sediment-interstitial water), usually expressed in l kg-1. It
is the ratio of the mass of the solute species adsorbed (or precipitated) on the
solid particles per unit of dry mass of the soil or sediment to the solute
concentration in the liquid phase. It represents the partition of the solute in the
soil or sediment matrix and soil or sediment water, assuming that equilibrium
conditions exist between the solid and liquid phases. The Kd values are
dependent on the soil or sediment physical and chemical characteristics.
Kerma Kerma is the kinetic energy released in material measured in Gy. Kerma can be
quoted for any specified material at a point in free space or in an absorbing
medium. See gamma air kerma.
Keystone species A species that plays a critical role in maintaining the structure of an ecological
community and whose impact on the community is greater than would be expected
based on its relative abundance or total biomass.
Indicator A species, whose presence or absence may be characteristic of environmental
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Organisms conditions in a particular area of habitat; however, species composition and
relative abundance of individual components of the population or community
are usually considered to be a more reliable index of water quality.
LEL Lowest Effect Level
LOEC, LOED(R) The lowest observed effect concentration in a toxicity test that causes a
statistically significant effect in comparison to the control. The same definition
applies for Dose or Dose Rate (in place of Concentration).
IUR International Union of Radioecology (http://www.iur-uir.org/en/)
Measurement Measured or predicted value that an assessment produces.
endpoint
Morbidity A loss of functional capacities generally manifested as reduced fitness, which
may render organisms less competitive and more susceptible to other stressors,
thus reducing the life span.
Mortality Death; the death rate; ratio of number of deaths to a given population.
NATURA 2000 Site A protected ecological area within the EU containing threatened habitats
and/or species.
Natural Background The doses, dose rates or activity concentrations associated with natural sources or
any other sources in the environment which are not amenable to control. This is
usually considered to include doses, dose rates or concentrations due to natural
sources but may also include global fallout (but not local fallout) from atmospheric
nuclear weapon tests and depending upon context, fallout from incidents such as
the Chernobyl accident.
NCRP National Council on Radiation Protection and Measurements, see
www.ncrponline.org
NEA Nuclear Energy Agency. A specialised agency within the Organisation for
Economic Co-operation and Development (OECD). See www.nea.fr
NEC No effect concentration, see NOEC, NOED(R)
NGO Non-Governmental Organisation
NoE Network of Excellence: EC funding mechanism
NOEC, NOED(R) No observed effect concentration is the highest concentration in a toxicity test
not causing a statistically significant effect compared with the control. The
same definition applies for Dose or Dose Rate (in place of Concentration). See
also HNEDR.
NPP Nuclear Power Plant
OECD Organisation for Economic Co-operation and Development, see www.oecd.org
Occupancy factors The maximum fraction of time during which individuals may be exposed to a given
dose rate of ionising radiation.
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OSPAR The mechanism by which 15 governments of the western coasts and
catchments of Europe, together with the EC, cooperate to protect the marine
environment of the North-East Atlantic.
PNED(R) Predicted No-Effect Dose (Rate) expressed in Gy or Gy per unit of time.
PNEC Predicted No-Effect Concentration, see NOEC, NOED(R) for No Effect
Concentration.
Precautionary The precautionary principle applies where scientific evidence is insufficient,
Principle inconclusive or uncertain and preliminary scientific evaluation indicates that there
are reasonable grounds for concern that the potentially dangerous effects on the
environment, human, animal or plant health may be inconsistent with the desired
level of protection.
PROTECT Protection of the Environment from Ionising Radiation in a Regulatory Context
Protection goal The measurable aims of environmental protection
Radiation Factor (numeric value) which represents the relative biological effectiveness of the
weighting factors different radiation types, relative to X- or gamma-rays, in producing endpoints of
ecological significance.
Radioactive Material designated in national law or by a regulatory body as being subject
Material to regulatory control because of its radioactivity.
Radioactive A substance that emits ionising radiation. See also radioactive material.
Substance
Radioecological A combination of features which includes biology and habits of an organism, that
Sensitivity contribute to the likelihood of an organism being exposed to radioactive
substances in its environment.
Radionuclide An unstable nuclide that undergoes spontaneous transformation, emitting
ionising radiation.
RAP Reference Animals and Plants: Group of 12 reference organisms proposed as part
of the ICPR framework.
RBE Relative Biological Effectiveness: For a given type of radiation, the RBE is the dose
of the reference radiation needed to produce the same effect dose of the given
radiation needed to produce a given biological effect.
REACH Registration, Evaluation and Authorisation of Chemicals and EU regulatory
framework
Receptor See ecological receptor
Reference A series of entities that provide a basis for the estimation of radiation dose rate
Organisms to a range of organisms that are typical, or representative, of a contaminated
environment. These estimates, in turn, would provide a basis for assessing the
likelihood and degree of radiation effects.
Relative Biological The proportion or absolute size of an exposed population that demonstrates a
Response specific effect. May also refer to the nature of the effect.
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RESRAD-BIOTA Radiological assessment tool which implements the US DoE's graded approach for
evaluating radiation doses to freshwater and terrestrial biota.
Risk A statistical concept describing the expected frequency or probability of
undesirable effects arising from exposure to a contaminant.
A measure of the probability that damage to life, health, property, and/or the
environment will occur as a result of a given hazard. A technical estimation of
risk is usually based on the expected value of the conditional probability of the
event occurring times the consequence or magnitude of the event given that it
has occurred.
Risk assessment A qualitative or quantitative evaluation of the risk posed to human health
and/or the environment by the actual and/or potential presence of contaminants.
It includes problem formulation, exposure and dose-response assessment and
risk characterisation.
Risk The synthesis of information obtained during risk assessment for use in
characterisation management decisions. This should include an estimation of the probability (or
incidence) and magnitude (or severity) of the adverse effects likely to occur in
a population or environmental compartment, together with identification of
uncertainties.
Risk The exchange of information about health or environmental risks among risk
communication assessors and managers, the general public, news media, interest groups, etc.
Risk evaluation A component of risk assessment in which judgments are made about the
significance and acceptability of risk.
Risk management The selection and practical implementation of regulatory and non-regulatory
responses to risk. Practical implementation of procedures, actions or policies to
mitigate, reduce, remove or monitor health or environmental risks.
RQ Risk Quotient: ratio of predicted dose rate to benchmark dose rate.
Safety factors See assessment factor (the favoured term used by PROTECT).
Screening Simple and generally highly conservative assessment tier.
assessment
Screening value In the context of PROTECT, the screening value is equivalent to the PNED(R).
SD Standard Deviation
SETAC Society of Environmental Toxicology and Chemistry
Source Anything that may cause radiation exposure — such as by emitting ionising
radiation or by releasing radioactive substances or materials — and can be
treated as a single entity for protection and safety purposes.
SSD Species Sensitivity Distribution establishing the statistical distribution of the
radiosensitivity of species.
Sustainability The ability of an ecosystem to maintain ecological processes and functions,
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biological diversity, and productivity over time.
Synergism An interaction between two substances that results in a greater effect than both
of the substances could have had acting independently.
TeNORM Technologically-Enhanced Naturally Occurring Radioactive Material. Refers to
radioactive materials that occur naturally but which have been exposed or
concentrated by human activity.
TGD European Chemicals Bureau Technical Guidance Document on risk assessment
(http://ecb.jrc.ec.europa.eu/DOCUMENTS/TECHNICAL_GUIDANCE_DOCUMENT
/EDITION_2/tgdpart2_2ed.pdf).
Threshold A contaminant concentration (or dose), below which no deleterious effect
occurs.
Tiered assessment Approach involving progressively detailed tiers of assessment generally starting
with highly conservative and simple ('screening') assessments and progressing
through more detailed realistic tiers if warranted.
Toxicant A substance that kills or injures an organism through chemical or physical
action or by altering the organism's environment; for example, cyanides,
phenols, pesticides, or heavy metals; especially used for insect control.
Trigger value See screening value
Uncertainty This arises from imprecision due to lack of information, expert judgement and/or
measurement errors and could be reduced with increased knowledge and/or
experimentation.
UNSCEAR United Nations Scientific Committee on the Effects of Atomic Radiation
USDoE United States Department of Energy
USDoE graded United States Department of Energy graded approach for evaluating radiation
approach doses to aquatic and terrestrial biota.
Valued ecosystem Assessed species selected for both scientific and public interest reasons.
components
WFD Water Framework Directive. EC water legislation for integrated river basin
management.

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