IUPAC Glossary of Terms Used in Toxicology – E
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ecogenetics
Study of the influence of hereditary factors on the effects of
xenobiotics on
individual organisms.
ecology
Branch of biology which studies the interactions between living
organisms and all factors (including other organisms) in their
environment: such interactions encompass environmental factors
which determine the distributions of living organisms.
ecosystem
Grouping of organisms (micro-organisms, plants, animals)
interacting together, with and through their physical and
chemical environments, to form a functional entity within a
defined environment.
ecotoxicologically (environmentally) relevant
concentration (ERC)
Concentration of a pesticide (active ingredient, formulations,
and relevant metabolites) that is likely to affect a determinable
ecological characteristic of an exposed system.
After [9]
ecotoxicology
Study of the toxic effects
of chemical and physical agents on all living organisms,
especially on populations and communities within defined
ecosystems; it includes
transfer pathways of these agents and their interactions with the
environment.
ectohormone
See pheromone
ectoparasiticide
Substance intended to kill parasites living on the exterior of
the host.
eczema
Acute or chronic skin inflammation with erythema, papules, vesicles, pustules,
scales, crusts or scabs, alone or in combination, of varied
etiology.
edema
oedema
Presence of abnormally large amounts of fluid in intercellular
spaces of body tissues.
effect biomarker
See biomarker of
effect
effective concentration (EC)
Concentration of a
substance that causes a defined magnitude of response in a given system.
Note: EC50 is the median concentration that causes 50
% of maximal response.
effective dose (ED)
Dose of a substance that
causes a defined magnitude of response in a given system.
Note: ED50 is the median dose that causes 50 % of
maximal response.
effluent
Fluid, solid or gas discharged from a given source into the
external environment.
element (in molecular biology)
Sequence in the promoter region of a gene that regulates expression of that
gene through interaction with a
trans-acting factor.
elimination (in toxicology)
Disappearance of a substance from an organism or a part thereof,
by processes of metabolism, secretion, or excretion.
[2]
See also clearance
elimination half-life or half time
Period taken for the plasma concentration of
a substance to decrease by half.
Note: May also be applied to other body compartments such as
blood, specific organs, or tissues.
elimination rate
Differential with respect to time of the concentration or amount of a
substance in the body, or a part thereof, resulting from
elimination.
[2]
eliminator (of a poison)
Substance that contributes to the elimination of a poison from an
organism.
- Stage in the developing mammal at which the characteristic organs and organ systems are being formed: for humans, this involves the stages of development from the second to the eighth week (inclusive post conception).
- In birds, the stage of development from the fertilization of the ovum up to hatching.
- In plants, the stage of development within the seed.
embryonic period
Period from fertilization to the end of major organogenesis.
[8]
embryotoxicity
- Production by a substance of toxic effects in progeny in the first period of pregnancy between conception and the fetal stage.
- Any toxic effect on the conceptus as a result of prenatal exposure during the embryonic stages of development: these effects may include malformations and variations, malfunctions, altered growth, prenatal death, and altered postnatal function.
embryotropic effect
Change in the embryo and the
regulation of its development.
emesis
Vomiting.
emission
discharge
effluent
release
Release of a substance from a source, including discharges to the
wider environment.
emission and exposure control
Technical and administrative procedures and specifications
applied for the monitoring, reduction or elimination of emissions from a source or exposure to a target.
emission standard
Quantitative limit on the emission or discharge of a substance from a
source, usually expressed in terms of a time-weighted average
concentration or a
ceiling value.
endemic
Present in a community or among a group of people; said of a
disease prevailing continually in a region.
endocon
Portion of a conjugated metabolite which is derived from a
natural product (such as a sugar, amino acid or other organic
acid) of the metabolizing organism.
See also exocon, phase II reaction.
After [6]
endocrine
Pertaining to hormones or to the glands that secrete hormones
directly into the bloodstream.
endocrine disrupter
endocrine modifier
Exogenous chemical that alters function(s) of the endocrine
system and consequently causes adverse health effects in an
intact organism, its progeny or (sub)populations.
[8]
endocrine modifier
See endocrine
disrupter
endocytosis
Uptake of material into a cell by
invagination of the plasma membrane
and its internalization in a membrane-bounded vesicle.
[2]
See also phagocytosis,
pinocytosis
endogenous
antonym exogenous
Produced within or caused by factors within an organism.
[2]
endoplasmic reticulum
Intracellular complex of membranes in which proteins and lipids,
as well as molecules for export, are synthesized and in which the
biotransformation
reactions of the mono-oxygenase enzyme systems occur.
Note: May be isolated as microsomes following cell fractionation
procedures.
endothelial
Pertaining to the layer of flat cells lining the inner surface of
blood and lymphatic vessels, and the surface lining of serous
and synovial membranes.
endothelium
Layer of flattened epithelial cells lining the heart, blood
vessels and lymphatic vessels.
[2]
endotoxin
Toxin that forms an integral
part of the cell wall of certain bacteria and is released only
upon breakdown of the bacterial cell.; endotoxins do not form
toxoids.
enteritis
Intestinal inflammation.
enterohepatic circulation
Cyclical process involving intestinal re-absorption of a substance that
has been excreted through the bile, followed by transfer back to
the liver, making it available for biliary excretion again.
environment
Aggregate, at a given moment, of all external conditions and
influences to which a system under study is subjected.
environmental damage
Adverse effects
to the natural environment.
environmental exposure level
(EEL)
Level (concentration or amount or a
time integral of either) of a substance to which an organism or
other component of the environment is exposed in its natural surroundings.
environmental fate
Destiny of a chemical or biological pollutant after release into the natural
environment.
environmental health
Human welfare and its influence by the environment, including
technical and administrative measures for improving the human
environment from a health
point of view.
environmental health impact assessment
Estimate of the adverse
effects to health
or risks likely to follow
from a proposed or expected environmental change or
development.
environmental health criteria documents
Critical publications of IPCS containing reviews of methodologies
and existing knowledge - expressed, if possible, in quantitative
terms - of selected substances (or groups of substances) on
identifiable, immediate, and long-term effects on human
health and welfare.
environmental hygiene
environmental sanitation
Practical control measures used to improve the basic
environmental conditions affecting human health, for example clean water supply,
human and animal waste
disposal, protection of food from biological contamination, and
housing conditions, all of which are concerned with the quality
of the human environment.
environmental impact assessment (EIA)
Appraisal of the possible environmental consequences of a past,
ongoing, or planned action, resulting in the production of an
environmental impact statement or ‘finding of no
significant impact (FONSI)’.
environmental impact statement (EIS)
Report resulting from an environmental impact
assessment.
environmental medicine
Specialty devoted to the prevention and management of
environmentally-induced injury, illness and disability, and the
promotion of the health of individuals, families, and communities
by ensuring a healthy environment.
environmental monitoring
Continuous or repeated measurement of agents in the environment
to evaluate environmental exposure and possible damage by comparison
with appropriate reference values based on knowledge of the
probable relationship between ambient exposure and resultant
adverse
effects.
environmental protection
- Actions taken to prevent or minimize adverse effects to the natural environment.
- Complex of measures including monitoring of environmental pollution, development and practice of environmental protection principles (legal, technical, and hygienic), including risk assessment, risk management and risk communication.
environmental quality objective (EQO)
Overall state to be aimed for in a particular aspect of the
natural environment, for example, “water in an estuary such
that shellfish populations survive in good health”.
Note: Unlike an environmental quality standard, the EQO is
usually expressed in qualitative and not quantitative terms.
environmental quality standard (EQS)
ambient standard
Amount concentration or mass
concentration of a substance that should not be exceeded in an
environmental system, often expressed as a time-weighted average measurement over a
defined period.
environmental risk assessment
Estimate of the probability that harm will result from a defined
exposure to a substance in an environmental medium. The estimate
is valid only for a given species and set of conditions.
environmental sanitation
See environmental
hygiene
environmental tobacco smoke (ETS)
See sidestream smoke
environmental transformation
Chemical transformation of substances resulting from interactions
in the environment.
environmentally relevant concentration
See ecotoxicologically
relevant concentration
enzootic
Present in a community or among a group of animals; said of a
disease prevailing continually in a region.
enzyme
Biological catalyst: a protein, nucleic acid or a conjugate of a
protein with another compound (coenzyme).
enzyme induction
Process whereby an enzyme is synthesized in response to a
specific substance or to other agents such as heat or a metal
species.
[2]
epidemiology
Study of the distribution and determinants of health-related states or events in
specified populations and the application of this study to
control of health problems.
epigastric
Pertaining to the upper-middle region of the abdomen.
epigen/esis n., -etic
adj.
Changes in an organism brought about by alterations in the
expression of genetic information without any change in the
genome itself (e.g. base
hypermethylation or histone modification).
Note: The genotype is
unaffected by such a change but the phenotype is altered.
epileptiform
Occurring in severe or sudden spasms, as in convulsion or
epilepsy.
epithelioma
Any tumor derived from epithelium.
epithelium
Sheet of one or more layers of cells covering the internal and
external surfaces of the body and hollow organs.
[2]
epitope
Any part of a molecule that acts as an antigenic determinant: a
macromolecule can contain many different epitopes each capable of
stimulating production of a different specific antibody.
equilibrium
State of a system in which the defining variables (temperature,
pressure, chemical potential) have constant values in time.
[2]
equivalent diameter (of a particle)
Diameter of a spherical particle of the same density as a
particle under investigation that, relative to a given phenomenon
or property, would behave in the same way as the particle under
investigation.
erythema
Redness of the skin produced by congestion of the
capillaries.
eschar
Slough or dry scab on an area of skin that has been burnt.
estimated daily intake (EDI)
Prediction of the daily intake of a residue of a potentially
harmful agent based on the most realistic estimation of the
residue levels in food and the best available food consumption
data for a specific population: residue levels are estimated
taking into account known uses of the agent, the range of
contaminated commodities, the proportion of a commodity treated,
and the quantity of home-grown or imported commodities.
Note: The EDI is expressed in mg residue per person.
estimated environmental concentration
(EEC)
Predicted concentration of a substance, typically a pesticide,
within an environmental compartment based on estimates
of quantities released, discharge patterns and inherent
disposition of the substance (fate and distribution) as well as
the nature of the specific receiving ecosystems.
See also expected environmental
concentration
After [9]
estimated exposure concentration (EEC)
Measured or calculated amount or mass concentration of a substance
to which an organism is likely to be exposed, considering exposure by all sources and routes.
estimated exposure dose (EED)
Measured or calculated dose
of a substance to which an organism is likely to be exposed, considering exposure by all sources and routes.
estimated maximum daily intake (EMDI)
Prediction of the maximum daily intake of a residue of a
potentially harmful agent based on assumptions of average food
consumption per person and maximum residues in the edible portion
of a commodity, corrected for the reduction or increase in
residues resulting from preparation, cooking, or commercial
processing.
Note: The EMDI is expressed in mg residue per person.
- Science dealing with the cause or origin of disease.
- In individuals, the cause or origin of disease.
eukaryote
antonym prokaryote
Cell or organism with the genetic material packed in a
membrane-surrounded structurally discrete nucleus and with
well-developed cell organelles.
Note: The term includes all organisms except archaebacteria,
eubacteria and cyanobacteria (until recently classified as
cyanophyta or blue-green algae).
European Inventory of Existing Chemical Substances
(EINECS)
List of all substances supplied either singly or as components in
preparations to persons in a Member State of the European
Community on any occasion between 1 January 1971 and 18 September
1981.
eutrophic
Describes a body of water with a high concentration of nutrient
salts and a high or excessive rate of biological production.
eutrophication
Adverse change in the chemical and biological status of a body of
water following depletion of the oxygen content caused by decay
of organic matter resulting from high primary production as a
result of enhanced input of nutrients.
excess lifetime risk
Additional or excess risk
incurred over the lifetime of an individual by exposure to a toxic substance.
excess rate
See rate difference
exchange transfusion
Method of active artificial elimination of toxicity
consisting in complete replacement of blood of the patient by
donor blood.
excipient
Any largely inert substance added to a drug to give suitable consistency or
form to the drug.
excitotoxicity
Pathological process by which neurons are damaged and killed by
the overactivation of receptors for the excitatory
neurotransmitter glutamate, such as the NMDA receptor and AMPA
receptor.
Note: Excitotoxins like NMDA and kainic acid bind to glutamate t
receptors, and can cause excitotoxicity by allowing high levels
of calcium ions to enter cells, activating enzymes such as
phospholipases, endonucleases, and proteases such as calpain
which damage cell structures including the cytoskeleton,
membranes, and DNA.
excretion
Discharge or elimination of
an absorbed or endogenous
substance, or of a waste
product, and (or) its metabolites, through some tissue of the
body and its appearance in urine, feces, or other products
normally leaving the body.
Note: Excretion does not include the passing of a substance
through the intestines without absorption.
[2]
See also clearance,
elimination
excretion rate
Amount of substance and (or) its metabolites that is excreted divided by
time of excretion.
[2]
exocon
Portion of a conjugated metabolite that is derived from the
parent molecule.
[6]
exogenous
antonym endogenous
Resulting from causes or derived from materials external to an
organism.
exogenous substance
See xenobiotic
exon
Coding section of a gene
that is separated from other coding sequences of the same
gene by intervening
noncoding sequences.
See intron
exothelium
Layer of flattened epithelial cells external to an organ or
tissue.
expected environmental concentration
(EEC)
Calculated concentrations of a substance, typically a pesticide,
in various environmental compartments based on calculations using
maximum-exposure scenarios.
Note: EEC models assume a maximum number of applications per
growing season at the maximum rate of application according to
the application methods stated on the product label.
After [10]
experimental model ecosystem
See microcosm
explant
Living tissue removed from its normal environment and transferred
to an artificial medium for growth.
exponential decay
Variation of a quantity according to the law
A = Ae– λt
where A and A0are the values of the
quantity being considered at time t and zero
respectively, and λ is an appropriate
constant.
[2]
exposed
antonyms non-exposed,
unexposed
Subject to a factor that is under study in the environment, for
instance an environmental hazard.
exposed group (sometimes abbreviated to
exposed) (in epidemiology)
People (or other organisms) who have been exposed to a supposed cause of a disease or
health state of interest, or
possess a characteristic that is a determinant of the health
outcome of interest.
- Concentration, amount or intensity of a particular physical or chemical agent or environmental agent that reaches the target population, organism, organ, tissue or cell, usually expressed in numerical terms of concentration, duration, and frequency (for chemical agents and micro-organisms) or intensity (for physical agents).
- Process by which a substance becomes available for absorption by the target population, organism, organ, tissue or cell, by any route.
- For X- or gamma radiation in air, the sum of the electrical
charges of all the ions of one sign produced when all electrons
liberated by photons in a suitably small element of volume of air
completely stopped, divided by the mass of the air in the volume
element.
[2]
exposure assessment
Process of measuring or estimating concentration (or intensity),
duration and frequency of exposures to an agent present in the
environment or, if estimating hypothetical exposures, that might
arise from the release of a substance, or radionuclide, into the
environment.
exposure biomarker
See biomarker of
exposure
exposure control
See emission and
exposure control
exposure-effect curve
See concentration-effect
curve
exposure limit
General term defining an administrative substance concentration or intensity of
exposure that should not be
exceeded.
exposure ratio
In a case control
study, value obtained by dividing the rate at which
persons in the case group are exposed to a risk factor (or to a protective factor)
by the rate at which persons
in the control group are exposed to the risk factor (or to the
protective factor) of interest.
exposure-response relationship
See concentration-response
relationship, dose-response
relationship
exposure surface
Surface on a target where a substance, e.g., a pesticide is
present. With mammals, examples of outer exposure surfaces
include the exterior of an eyeball, the skin surface and a
conceptual surface over the nose and open mouth. Examples of
inner exposure surfaces include the gastrointestinal tract, the
respiratory tract and the urinary tract lining.
[12]
exposure test
Determination of the level, concentration or uptake of a potentially toxic compound and (or) its metabolite(s) in biological samples from an organism (blood, urine,
hair etc.) and the interpretation of the results to estimate the
absorbed dose or degree of environmental pollution; or the measuring of
biochemical effects, usually not direct adverse effects of the
substance, and relating them to the quantity of substance
absorbed, or to its concentration in the environment.
expressed sequence tag
(EST)
Partial or full complementary DNA sequence which can serve as a
marker for a region of the genome which encodes an expressed
product.
[9]
expression (in genetics)
Conversion of the genetic information encoded in DNA into a final
gene product (either a protein or any of the different types of
RNA).
Note: Because changes in RNA synthesis are often estimated by
measuring mRNA levels, the term “gene expression” is
often misleadingly used as synonymous with transcription. The
term “gene expression” includes transcription,
processing, and splicing of mRNA, as well as translation, and
post-translational modification of the protein product.
external validity
Generalizability of the results of a particular study, beyond the
limits of the population actually studied.
extracellular space
Volume within a tissue, outside cells and excluding vascular and
lymphatic space.
[2]
extracellular volume
Volume of fluid outside the cells but within the outer surface of
an organism.
[2]
extraction ratio
Amount of substance extracted from a source divided by the total
contained within the source.
[2]
extra risk
Probability that an agent produces an observed response,
as distinguished from the probability that the response is caused
by a spontaneous event unrelated to the agent.
extraneous residue limit (ERL)
Refers to a pesticide residue or contaminant arising from
environmental sources (including former agricultural uses) other
than the use of a pesticide or contaminant substance directly or
indirectly on the commodity. It is the maximum concentration of a pesticide
residue or contaminant that is recommended by the Codex Alimentarius Commission to be
legally permitted or recognized as acceptable in or on food,
agricultural commodity or animal feed.
Note: The mass content is expressed in milligrams of pesticide
residue or contaminant per kilogram of commodity.
extrapolation
Calculation, based on quantitative observations in exposed test species or in vitro test systems, of predicted dose-effect and dose-response
relationships
for a substance in humans and other biota including interspecies
extrapolations and extrapolation to susceptible groups of
individuals.
Note: The term may also be used for qualitative information
applied to species or conditions that are different from the ones
in which the original investigations were carried out.
extrapyramidal movement disorders
Involuntary movements, e.g., those that occur as a side effect of
psychiatric medications.