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Pure Appl. Chem., Vol. 65, No. 9, pp. 2003-2122, 1993.



Glossary for chemists of terms used in toxicology
(IUPAC Recommmendations 1993)


Alphabetical entries

A | B | C | D | E | F | G | H | I | J | K | L | M

N | O | P | Q | R | S | T | U | V | W | X | Y | Z

safety: 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, risk.
safety data sheet: Single page giving toxicological and other safety advice, usually associated with a particular preparation, substance or process.
safety factor: See SN uncertainty factor.
saluretic: See SN natriuretic.
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.
   PAC, 1990
RT biased sample, random sample, stratified sample, systematic sample.
sampling: Procedure used to obtain or constitute a sample.
RT sample
sampling error: 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.
ISO, 1977
RT sample, sampling.
sarcoma: Malignant tumour arising in a connective tissue and composed primarily of anaplastic cells resembling supportive tissue.
saturnism: Intoxication caused by lead.
SN plumbism.
scotoma: Area of depressed vision within the visual field, surrounded by an area of less depressed or normal vision.
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.
screening level: Decision limit or cut-off point at which a screening test is regarded as positive.
Last, 1988
secondary metabolite: 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), 1991
secondary pollutant: See BT pollutant.
secondhand smoke: See SN sidestream smoke.
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 cell
   through a plasma membrane to the outside as a result of cell activity.
sedative: Substance that exerts a soothing or tranquillising effect.
RT anaesthetic, narcotic.
self-cleaning of water (in a reservoir): Water purification by natural biological and physico-chemical processes.
self-purification of the atmosphere: Purification of the atmosphere from contaminants by natural biological and physico-chemical processes.
RT contaminant.
semichronic: See SN subchronic.
sensibilization: See SN sensitization.
sensitivity (in analytical chemistry): Extent to which a small change in concentration of an analyte can cause a large change in the related measurement.
Gold, Loening, McNaught and Sehmi, 1987
sensitivity (of a screening test): 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)
sensitization: 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 material (allergen).
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 alone.
RT nuisance threshold.
WHO, 1987
1. Watery proteinaceous portion of the blood that remains after clotting.
   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 effect: See SN acute effect.
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.
   BT pneumoconiosis.
2. Excess of iron in the urine, blood or tissues, characterized by haemosiderin granules in urine and iron
   deposits in tissues..
sidestream smoke: 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.
silicosis: Pneumoconiosis resulting from inhalation of silica dust.
BT pneumoconiosis.
simulation test: Procedure designed to predict the rate of biodegradation of a compound under relevant environmental conditions.
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 the air.
sister chromatid exchange (SCE): Reciprocal 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.
RT mitosis.
skeletal fluorosis: Osteosclerosis due to fluoride.
slimicide: Substance intended to kill slime-producing organisms (used on paper stock, water cooling systems, paving stones etc.).
slope factor: Value, in inverse concentration or dose units, derived from the slope of a dose-response curve; in practice, limited to carcinogenic effects with the curve assumed to be linear at low concentrations or doses. The product of the slope factor and the exposure is taken to reflect the probability of producing the related effect.
RT concentration-effect curve, concentration-response curve, dose, dose-effect curve, dose-response curve.
societal risk: 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.
solvent abuse: Deliberate inhalation (or drinking) of volatile solvents, in order to become intoxicated.
SN "solvent sniffing".
NT "glue sniffing".
"solvent sniffing": See SN solvent abuse.
NT "glue sniffing".
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.
soporific: Substance producing sleep.
RT anaesthetic, narcotic, sedative.
sorption: Noncommittal term used instead of adsorption or absorption when it is difficult to discriminate experimentally between these two processes.
Gold, Loening, McNaught and Sehmi, 1987
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.
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.
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 in sensitivity.
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).
IPCS, 1987
specificity (of a screening test): Proportion of truly non-diseased persons who are identified by the screening test.
specific pathogen free (SPF): Describing 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.
specimen: 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 or demonstration.
PAC, 1990
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 %).
Brown, 1988
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 level.
   SN technical directive.
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.
standard material (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
   PS reference material.
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.
Last, 1988

stannosis: Pneumoconiosis resulting from inhalation of tin dust.
stochastic: Of, pertaining to or arising from chance and hence involving probability and obeying the laws of probability.
stochastic effect: 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.
WHO, 1989a
RT all-or-none effect, quantal effect.
stratification (in epidemiology): Process of or result of separating a sample into several subsamples according to specified criteria such as age groups, socio-economic status, etc.
Last, 1988
stratified sample: Subset of a population selected according to some important characteristic.
RT stratification.
structure-activity relationship (SAR): Association between the physicochemical properties of a substance and/or the properties of its molecular substructures and its biological properties including its toxicity.
PS quantitative structure-activity relation (QSAR).
subacute: Term used to describe a form of repeated exposure or administration usually occurring over about 21 days, not long enough to be called "long-term" or "chronic".
PS subchronic.
RT subacute effect, subchronic effect, subchronic toxicity, subchronic toxicity test.
subacute (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 case.
PS subchronic effect.
RT subchronic toxicity, subchronic toxicity test.
subchronic: Related to repeated dose exposure over a short period, usually about 10 % of the life span; an imprecise term used to describe exposures of intermediate duration.
PS subacute.
RT subacute effect, subchronic effect, subchronic toxicity, subchronic toxicity test.
SN semichronic.
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.
PS subacute effect.
RT subchronic toxicity, subchronic toxicity test.
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 exposure.
RT subacute, subchronic, subchronic effect, subchronic toxicity test.
subchronic (sometimes called subacute) toxicity test: Animal experiment 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.
WHO, 1979
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.
subjective environment: Surrounding conditions as perceived by persons living in these conditions.
SN perceived environment.
After WHO, 1979
subthreshold dose: See SN non-effective dose
sudorific: Substance that causes sweating.
sufficient evidence: 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 in question.
RT carcinogenicity, classification according to IARC, limited evidence.
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.
summary sheet: Two-to-four page summary of a risk assessment.
IRIS, 1986
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.
Superfund: 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.
IRIS, 1986
super-threshold dose: See PS toxic dose.
surface layer: 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.
surrogate: Relatively 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.
RT quantitative structure-activity relationship.
surveillance: 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 measures.
Last, 1988
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.
SN antiadrenergic.
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.
SN adrenergic.
symptom: Any subjective evidence of a disease or an effect induced by a substance as perceived by the affected subject.
symptomatology: 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.).
Brown, 1988
synapse: Functional junction between two neurones, where a nerve impulse is transmitted from one neurone to another.
synaptic transmission: See RT synapse.
syndrome: Set of signs and symptoms occurring together and often characterizing a particular disease-like state.
synergism: Pharmacological 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.
synergistic effect: 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, potentiation.
systematic sample: Subset selected according to some simple rule such as specified date or alphabetic classification.
RT biased sample, stratified sample.
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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