Organizations & People
Pure Appl. Chem.,
Vol. 65, No. 9, pp. 2003-2122, 1993.
COMMISSION ON TOXICOLOGY
Glossary for chemists of terms used in toxicology
(IUPAC Recommmendations 1993)
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: Reciprocal of
risk: practical certainty that injury will not result from a hazard
under defined conditions.
1. Safety of a drug or other substance in the context of human health:
the extent to which a substance may
be used in the amount necessary for the intended purpose
with a minimum risk of adverse health effects.
2. Safety (toxicological): The high probability that injury will
not result from exposure to a substance
under defined conditions of quantity and manner of
use, ideally controlled to minimize exposure.
RT practical certainty,
safety data sheet
Single page giving toxicological and other safety advice, usually
associated with a particular preparation, substance or process.
1. In statistics, a group of individuals often taken at random from
a population for research purposes
2. One or more items taken from a population or a process and intended
to provide information on the
population or process.
3. Portion of material selected from a larger quantity in some manner
chosen so that the portion is
representative of the whole.
RT biased sample, random
sample, stratified sample,
used to obtain or constitute a sample.
: Part of the total estimation
error of a parameter (or value of a property, such as concentration)
caused by the random nature of the sample.
RT sample, sampling
sarcoma: Malignant tumour arising in a connective
tissue and composed primarily of anaplastic cells resembling supportive
caused by lead.
scotoma: Area of depressed vision within
the visual field, surrounded by an area of less depressed or normal
sclerosis: Hardening of an organ or tissue,
especially that due to excessive growth of fibrous tissue.
1. Carrying out of a test or tests, examination(s) or procedure(s)
in order to expose undetected
abnormalities, unrecognized (incipient) diseases, or
defects: examples are mass X-rays and cervical
2. Pharmacological or toxicological screening consists of a specified
set of procedures to which a series of
compounds is subjected to characterize pharmacological
and toxicological properties and to establish
dose-effect and dose-response relationships.
: Decision limit or cut-off
point at which a screening test is regarded as positive.
: Product of biochemical
processes other than the normal metabolic pathways, mostly produced
in micro-organisms or plants after the phase of active growth and
under conditions of nutrient deficiency.
After Nagel et al. (eds),
1. Process by which a substance such as a hormone or enzyme produced
in a cell is passed through a plasma
membrane to the outside, for example the intestinal
lumen or the blood (internal secretion).
2. Solid, liquid or gaseous material passed from the inside of a
through a plasma membrane to the outside as a result
of cell activity.
self-cleaning of water (in a reservoir):
Water purification by natural biological and physico-chemical processes.
self-purification of the atmosphere
of the atmosphere from contaminants by natural biological and physico-chemical
sensitivity (of a screening
: Extent (usually expressed as a percentage) to which a
method gives results that are free from false negatives; the fewer
the false negatives, the greater the sensitivity.
Quantitatively, sensitivity is the proportion of truly diseased
persons in the screened population who are identified as diseased
by the screening test.
Galen and Gambino, 1975
RT specificity (of a screening test)
Immune process whereby individuals become hypersensitive to substances,
pollen, dandruff, or other agents that make them develop a potentially
harmful allergy when they are subsequently exposed to the sensitizing
RT allergy, hypersensitivity
sensory effect level:
1. Intensity, where the detection threshold level is defined as
the lower limit of the perceived intensity
range (by convention the lowest concentration that
can be detected in 50 % of the cases in which it is
2. Quality, where the recognition threshold level is defined as
the lowest concentration at which the
sensory effect can be recognized correctly in 50 %
of the cases.
3. Acceptability and annoyance, where the nuisance threshold level
is defined as the concentration at which
not more than a small proportion of the population,
less than 5 %, experiences annoyance for a small part
of the time, less than 2 %; since annoyance will be
influenced by a number of factors, a nuisance
threshold level cannot be set on the basis of concentration
RT nuisance threshold
1. Watery proteinaceous portion of the blood that remains after
SN blood serum.
2. Clear watery fluid especially that moistening the surface of
serous membranes or that exuded through
inflammation of any of these membranes.
short term exposure limit (STEL): As used
by US NIOSH, unless noted otherwise, the 15 minute time weighted
average exposure that should not be exceeded at any time during
a work day.
side-effect: Action of a drug other than
that desired for beneficial pharmacological effect.
1. Pneumoconiosis resulting from the inhalation of iron dust.
2. Excess of iron in the urine, blood or tissues, characterized
by haemosiderin granules in urine and iron
deposits in tissues..
Cloud of small particles and gases that is given off from the end
of a burning tobacco product (cigarette, pipe, cigar) between puffs
and is not directly inhaled by the smoker; the smoke that gives
rise to passive inhalation on the part of bystanders.
SN secondhand smoke
RT mainstream smoke
sign: Objective evidence of a disease, deformity
or an effect induced by an agent, perceptible to an examining physician.
resulting from inhalation of silica dust.
simulation test: Procedure designed to predict
the rate of biodegradation of a compound under relevant environmental
sink: In environmental chemistry, an area
or part of the environment in which, or a process by which, one
or more pollutants is removed from the medium in which it is dispersed;
for example - moist ground acts as a sink for sulfur dioxide in
sister chromatid exchange (SCE)
exchange of chromatin between two replicated chromosomes that remain
attached to each other until anaphase of mitosis; used as a measure
of mutagenicity of substances that produce this effect.
skeletal fluorosis: Osteosclerosis due to
slimicide: Substance intended to kill slime-producing
organisms (used on paper stock, water cooling systems, paving stones
Total probability of harm to a human population including also the
probability of adverse health effects to descendants and the probability
of disruption resulting from loss of services such as
industrial plant or loss of material goods and electricity.
1. Pertaining to the body as opposed to the mind.
2. Pertaining to nonreproductive cells or tissues.
3. Pertaining to the framework of the body as opposed to the viscera.
speciation: Determination of the exact chemical
form or compound in which an element occurs in a sample, for instance
- determination of whether arsenic occurs in the form of trivalent
or pentavalent ions or as part of an organic molecule, and the quantitative
distribution of the different chemical forms that may coexist.
1. In biological systematics, group of organisms of common ancestry
that are able to reproduce only among
themselves and that are usually geographically distinct.
2. See NT chemical species
differences in sensitivity
: Quantitative or qualitative differences
of response to the action(s) of a potentially toxic substance on
various species of living organisms.
RT species-specific sensitivity
: Quantitative and qualitative features of response
to the action(s) of a potentially toxic substance that are characteristic
for particular species of living organism.
RT species differences
specific death rate: Death rate computed
for a subpopulation of individual organisms or people having a specified
characteristic or attribute, and named accordingly (for example,
age-specific death rate, the number of deaths of persons of a specified
age during a given period of time, divided by the total number of
persons of that age in the population during that time).
specificity (of a screening
: Proportion of truly non-diseased persons who are identified
by the screening test.
specific pathogen free (SPF)
an animal removed from its mother under sterile conditions just
prior to term and subsequently reared and kept under sterile conditions.
RT germ-free animal
: Specifically selected portion of
any substance, material, organism (specifically tissue, blood, urine
or faeces) or environmental medium assumed to be representative
of the parent substance etc. at the
time it is taken for the purpose of diagnosis, identification, study
spreader: Agent used in some pesticide formulations
to extend the even disposition of the active ingredient.
stability half-life (half-time)
: Time required
for the amount of a substance in a formulation to decrease, for
any reason, by one-half (50 %).
1. That which is established as a measure or model to which others
of a similar nature should conform.
2. Technical specification, usually in the form of a document available
to the public, drawn up with the
consensus or general approval of all interests affected
by it, based on the consolidated results of
science, technology and experience, aimed at the promotion
of optimum community benefits and approved by
a body recognized on the national, regional or international
3. Reference substance.
SN standard material
1. Making any substance, drug or other preparation conform to type
or precisely defined characteristics.
2. Establishment of precisely defined characteristics, or precisely
defined methods, for future reference.
3. Definition of precise procedures for administering, scoring and
evaluating the results of a new method
that is under development.
(in analytical chemistry):
1. Reference material (or calibration material) for which, for specified
element concentrations, values are
recommended by some official body.
Gold, Loening, McNaught
and Sehmi, 1987
2. Substance sufficiently well defined to be used for calibration
and quality control of measurement
standard(ized) mortality (morbidity) ratio (SMR)
Ratio of the number of events observed in the study group or population
to the number of deaths expected if the study population had the
same specific rates as the standard population, multiplied by 100.
: Pneumoconiosis resulting from inhalation of tin
stochastic: Of, pertaining to or arising
from chance and hence involving probability and obeying the laws
Consequence for which the probability of occurrence depends on the
absorbed dose: hereditary effects and cancer induced by radiation
are considered to be stochastic effects. The term "stochastic" indicates
that the occurrence of effects so named, would be random. This means
that, even for an individual, there is no threshold of dose below
which the effect will not appear, and the chance of periencing the
effect increases with increasing dose.
RT all-or-none effect,
: Process of or result of separating a sample into
several subsamples according to specified criteria such as age groups,
socio-economic status, etc.
Subset of a population selected according to some important characteristic.
structure-activity relationship (SAR)
between the physicochemical properties of a substance and/or the
properties of its molecular substructures and its biological properties
including its toxicity.
structure-activity relation (QSAR).
(sometimes called subchronic) effect:
Biological change resulting
from multiple or continuous exposures usually occurring over about
21 days. Sometimes the term is used synonymously with subchronic
effect and care should be taken to check the usage any particular
RT subchronic toxicity, subchronic
(sometimes called subacute) effect:
Biological change resulting
from an environmental alteration lasting about 10 % of the lifetime
of the test organism . In practice with experimental animals, such
an effect is usually identified as resulting from multiple or continuous
exposures occurring over 3 months (90 days). Sometimes a subchronic
effect is distinguished from a subacute effect on the basis of its
lasting for a much longer time.
RT subchronic toxicity,
1. Adverse effects resulting from repeated dosage or exposure to
a substance over a short period, usually
about 10 % of the life span.
2. The capacity to produce adverse effects following subchronic
RT subacute, subchronic,
(sometimes called subacute) toxicity test:
serving to study the effects produced by the test material when
administered in repeated doses (or continually in food, drinking-water,
air) over a period of up to about 90 days.
SN semichronic toxicity test
subclinical effect: Biological change following
exposure to an agent known to cause disease either before symptoms
of the disease occur or when they are absent.
that causes sweating.
: According to the USEPA's
Guidelines for Carcinogen Risk Assessment, sufficient evidence is
a collection of facts and scientific references that is definite
enough to establish that an adverse effect is caused by the agent
classification according to IARC, limited
suggested no adverse response level (SNARL):
Maximum dose or concentration that on current understanding is likely
to be tolerated by an exposed organism without producing any harm.
: Two-to-four page summary of
a risk assessment.
summation (in neurophysiology)
Process of addition of separate postsynaptic responses caused by
stimuli that are adjacent in time and space. Excitation of a synapse
evokes a graded potential change in the postsynaptic membrane that
may be below the threshold required to trigger an impulse. If two
or more such potentials are caused either nearly simultaneously,
at different synapses on the same neurone (spatial summation), or
in rapid succession at the same synapse (temporal summation), the
summed response may
be sufficient to trigger a postsynaptic impulse. Summation may occur
between excitatory potentials, inhibitory potentials, or between
an excitatory and an inhibitory potential.
: Federal authority, established
by the US Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) in 1980, to respond directly to releases
or threatened releases (such as from dumps)
of hazardous substances that may endanger health or welfare.
Region of space comprising and adjoining the phase boundary between
a solid and liquid phase, between a solid and gas phase, or between
a liquid and gas phase within which properties of matter are significantly
different from the values in the adjoining bulk phases.
PS interfacial layer
well studied toxicant whose properties are assumed to apply to an
entire chemically and toxicologically related class; for example,
benzo(a)pyrene data may be used as toxicologically equivalent to
that for all carcinogenic polynuclear aromatic hydrocarbons.
: Ongoing scrutiny, generally
using methods distinguished by their practicability and uniformity,
and frequently by their rapidity, rather than by complete accuracy.
Its main purpose is to detect changes in
trend or distribution in order to initiate investigative or control
susceptibility: Condition of lacking the
power to resist a particular disease or infection; thus in susceptible
people "normal expected" results occur but with a lower exposure
(or dose) than in the rest of the population.
1. adj., Blocking transmission of impulses from the adrenergic (sympathetic)
postganglionic fibres to
effector organs or tissues.
2. n., Agent that blocks transmission of impulses from the adrenergic
(sympathetic) postganglionic fibres to
effector organs or tissues.
1. adj., Producing effects resembling those of impulses transmitted
by the postganglionic fibres of the
sympathetic nervous system.
2. n., Agent that produces effects resembling those of impulses
transmitted by the postganglionic fibres of
the sympathetic nervous system.
symptom: Any subjective evidence of a disease
or an effect induced by a substance as perceived by the affected
: General description of all
of the signs and symptoms of exposure to a toxicant: signs are the
overt (observable) responses associated with exposure (such as convulsions,
death, etc.) whereas symptoms
are covert (subjective) responses (such as nausea, headache, etc.).
junction between two neurones, where a nerve impulse is transmitted
from one neurone to another.
: See RT synapse
syndrome: Set of signs and symptoms occurring
together and often characterizing a particular disease-like state.
or toxicological interaction in which the combined biological effect
of two or more substances is greater than expected on the basis
of the simple summation of the toxicity of each of
the individual substances.
: Biological effect following
exposure simultaneously to two or more substances that is greater
than the simple sum of the effects that occur following exposure
to the substances separately.
RT additive effect, antagonism,
Subset selected according to some simple rule such as specified
date or alphabetic classification.
RT biased sample, stratified
systemic: Relating to the body as a whole.
systemic effect: Consequence
that is of either a generalized nature or that occurs at a site
distant from the point of entry of a substance: a systemic effect
requires absorption and distribution of the substance in the body.
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