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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


back-mutation: Process which reverses the effect of a mutation which had inactivated a gene; thus it restores the wild phenotype.
RT phenotype.

bactericide: Substance intended to kill bacteria.

bagassosis: Lung disease caused by the inhalation of dust from sugar-cane

base pairing: Linking of the complementary pair of polynucleotide chains of nucleic acids by means of hydrogen bonds between complementary purine and pyrimidine bases, adenine with thymine or uracil, cytosine with guanine.

B-cell: See B lymphocyte.

benefit: Advantage to or improvement in condition of an individual or a population.

1. Of a disease, producing no persisting harmful effects.
2. Tumour which does not invade other tissues (metastasize), having lost growth control but not positional control.
AN malignant

berylliosis: See SN beryllium disease

beryllium disease: Serious and usually permanent lung damage resulting from chronic inhalation of beryllium.

bias: Deviation of results or inferences from the truth, or processes leading to such deviation. Any trend in the collection, analysis, interpretation, publication, or review of data which can lead to conclusions which are systematically different from the truth. Among the ways in which deviation from the truth can occur are the following:

1. Systematic (one-sided) variation of measurements from the true values
   SN systematic error.
2. Variation of statistical summary measures (means, rates, measures of association, etc.) from their true values as a
   result of systematic variation of measurements, other flaws in data collection, or flaws in study design or analysis.
3. Deviation of inferences from the truth as a result of flaws in study design, data collection, or the analysis or
   interpretation of results.
4. A tendency of procedures (in study design, data collection, analysis, interpretation, review or publication) to yield
   results or conclusions which depart from the truth.
5. Prejudice leading to the conscious or unconscious selection of study procedures which depart from the truth in a
   particular direction, or to one-sidedness in the interpretation of results.
Last, 1988

biased sample: Any sample which is not a random sample.
AN random sample.
BT sample.
RT stratified sample, systematic sample.

bilirubin: Orange-yellow pigment (C33H36O6N4), a breakdown product of haem-containing proteins (haemoglobin, myoglobin, cytochromes), which circulates in the blood plasma bound to albumin or as water soluble glucuronides, and is excreted in the bile by the liver.

bioaccumulation: Progressive increase in the amount of a substance in an organism or part of an organism which occurs because the rate of intake exceeds the organism's ability to remove the substance from the body.
PS bioconcentration, biomagnification.

bioaccumulation potential: Ability of living organisms to concentrate a substance obtained either directly from the environment or indirectly through its food.
IPCS, 1987

bioactivation: Any metabolic conversion of a xenobiotic to a more toxic derivative.
PS activation.
BT biotransformation.

bioassay: Procedure for estimating the concentration or biological activity of a substance (vitamin, hormone, plant growth factor, antibiotic etc.) by measuring its effect on an organism compared to an appropriate standard preparation.
Nagel et al. (eds), 1991
BT assay.

1. Extent to which a substance to which the body is exposed (by ingestion, inhalation, injection, or skin contact) reaches
   the systemic circulation, and the rate at which this occurs.
   SN biological availability, physiological availability.
2. Pharmacokinetic term relating systemic exposure from extravascular exposure (ev) to that following intravenous exposure
   (iv) by the equation:
                           F = AUCev*Div / AUCiv*Dev
where F is the bioavailability, AUCev and AUCiv are the areas under the plasma concentration time curve following extravascular and intravenous administration and Dev and Div are the administered extravascular and intravenous doses.

biochemical mechanism: Reaction or series of reactions, usually enzyme-catalysed, associated with a specific physiological event in a living organism.

biochemical (biological) oxygen demand (BOD): Substance concentration of oxygen taken up through the respiratory activity of micro-organisms growing on organic compounds present when incubated at a specified temperature (usually 20 o C) for a fixed period (usually 5 days). It is regarded as a measure of that organic pollution of water which can be degraded biologically
but includes the oxidation of inorganic material such as sulfide and iron(II). The empirical test used in the laboratory to determine BOD also measures the oxygen used to oxidize reduced forms of nitrogen unless their oxidation is prevented by an inhibitor such as allyl thiourea.
RT chemical oxygen demand.
Nagel et al. (eds), 1991

biocid/e n., -al adj.: Substance intended to kill living organisms.

bioconcentration: Process leading to a higher concentration of a substance in an organism than in environmental media to which it is exposed.
PS bioaccumulation, biomagnification.
After WHO, 1979

bioconcentration factor (BCF): Measure of the tendency for a substance in water to accumulate in fish tissue or in tissues of other organisms. The equilibrium concentration of a substance in fish can be estimated by multiplying the concentration of the substance in the surrounding water by the fish bioconcentration factor for that chemical. This parameter is an
important determinant for human intake by the aquatic food ingestion route.
After USEPA, 1986

bioconversion: See SN biotransformation.

biodegradation: Breakdown of a substance catalysed by enzymes in vitro or in vivo. This may be characterized for purposes of hazard assessment as:
1. Primary. Alteration of the chemical structure of a substance resulting in loss of a specific property of that substance.
2. Environmentally acceptable. Biodegradation to such an extent as to remove undesirable properties of the compound. This
   often corresponds to primary biodegradation but it depends on the circumstances under which the products are discharged
   into the environment.
3. Ultimate. Complete breakdown of a compound to either fully oxidised or reduced simple molecules (such as carbon
   dioxide/methane, nitrate/ammonium, and water.
It should be noted that the products of biodegradation can be more harmful than the substance degraded.
RT biotransformation.

bio-elimination: Removal, usually from the aqueous phase, of a test substance in the presence of living organisms by biological processes supplemented by physico-chemical reactions.

bio-equivalen/ce n., -t adj.: Relationship between two preparations of the same drug in the same dosage form that have a similar bioavailability.

biological absorption: See absorption, biological.

biological acclimatization: See acclimatization, biological.

biological assessment of exposure:
1. Assessment of exposure to a substance by the analysis of specimens taken in the environment such as foodstuffs, plants,
   animals, biological material in air or water samples, or biological material from exposed subjects. When human samples
   are analysed, they are usually urine and blood; other possible samples include expired air, faeces, saliva, bile, hair,
   and biopsy or autopsy material. When other organisms are being considered, the whole organism may be analysed as well as
   selected tissues such as fat in pigs or birds. In these samples, the content(s) of the substance(s) or metabolite(s)
   is determined and, on this basis, the exposure level (concentration in the air, absorbed amount of the substance) or the
   probability of health impairment due to exposure are derived.
2. Biochemical changes in the components of an organism, such as changes in enzyme activity or in the excretion of
   metabolic intermediates, can also be used for this purpose if they show a relationship to the exposure.
BT biological monitoring, monitoring.

biological cycle: Complete circulatory process through which a substance passes in the biosphere. It may involve transport through the various media (air, water, soil), followed by environmental transformation, and carriage through various ecosystems.
WHO, 1979
RT biosphere, ecosystem.

biological effect monitoring (BEM): Continuous or repeated measurement of early biological effects of exposure to a substance to evaluate ambient exposure and health risk by comparison with appropriate reference values based on knowledge of the probable relationship between ambient exposure and biological effects.
BT biological monitoring, environmental monitoring.

biological half-life or half-time(t1/2): Time required for the amount of a substance in a biological system to be reduced to one-half, predominantly by biological processes, when the rate of removal is approximately exponential.
Gold, Loening, McNaught and Sehmi, 1987

biological monitoring: Continuous or repeated measurement of potentially toxic substances or their metabolites or biochemical effects in tissues, secreta, excreta, expired air or any combination of these in order to evaluate occupational or environmental exposure and health risk by comparison with appropriate reference values based on knowledge of the
probable relationship between ambient exposure and resultant adverse health effects.
NT biological effect monitoring
BT environmental monitoring, monitoring.
RT biological assessment of exposure.

biological oxygen demand: See SN biochemical oxygen demand.

biological preparation: Compound derived from living organisms and their products for use in medicine or as a pesticide etc.
SN biological, biopreparation.

biological specimen:
1. Organ, tissue (including blood), secretion or excretion product taken from an organism as a sample reflecting the state
   of the whole organism.
2. Organism taken as a sample reflecting the state of a population or their environment.

biomagnification: Sequence of processes in an ecosystem by which higher concentrations are attained in organisms at higher trophic levels (at higher levels in the food web); at its simplest, a process leading to a higher concentration of a substance in an organism than in its food.
SN ecological magnification.
RT bioaccumulation, bioconcentration.

1. Parameter that can be used to identify a toxic effect in an individual organism and can be used in extrapolation between
2. Indicator signalling an event or condition in a biological system or sample and giving a measure of exposure, effect, or

1. Total amount of biotic material, usually expressed per unit surface area or volume, in a medium such as water.
   WHO, 1979
2. Material produced by the growth of micro-organisms, plants or animals.
   Nagel et al. (eds), 1991

biomineralization: Complete conversion of organic substances to inorganic derivatives by living organisms, especially micro-organisms.

biomonitoring: See SN biological monitoring.

biopsy: Excision of a small piece of living tissue for microscopic or biochemical examination; usually performed to establish a diagnosis.
RT autopsy.

biosphere: Portion of the planet earth which supports and includes life.

biostatic: Arresting the growth or multiplication of living organisms.

biota: All living organisms as a totality.

biotransformation: Any chemical conversion of substances that is mediated by living organisms or enzyme preparations derived therefrom.
Nagel et al. (eds), 1991

blood substitution: See SN exchange transfusion.

B lymphocyte: Type of lymphocyte which synthesizes and secretes antibodies in response to the presence of a foreign substance or one identified by it as foreign. The protective effect can be mediated to a certain extent by the antibody alone (contrast T lymphocyte).
RT immune response, lymphocyte, T lymphocyte.

body burden: Total amount of substance of a chemical present in an organism at a given time.

1. Single dose of a substance, originally a large pill.
2. Dose of a substance administered by a single rapid intravenous injection.
3. Concentrated mass of food ready to be swallowed.

brady-: Prefix meaning slow as in bradycardia or bradypnoea.

bradycardia: Abnormal slowness of the heartbeat.
AN tachycardia.

bradypnoea: Abnormally slow breathing.
AN tachypnoea.

breathing zone: Space within a radius of 0.5 m from a person's face.
IRPTC, 1982

British anti-Lewisite (BAL): See SN 2,3-dimercaptopropan-1-ol.

bronchoconstriction: Narrowing of the air passages through the bronchi of the lungs.
AN bronchodilation.

bronchodilation: Expansion of the air passages through the bronchi of the lungs.
AN bronchoconstriction.

bronchospasm: Intermittent violent contraction of the air passages of the lungs.

builder: Material which enhances or maintains the cleaning efficiency of a surfactant, in a detergent, principally by inactivating water hardness; complex phosphates (especially sodium tripolyphosphate, i.e. pentasodium triphosphate), sodium carbonate, and sodium silicate are the builders most commonly used.

byssinosis: Pneumoconiosis caused by inhalation of dust and associated microbial contaminants and observed in cotton, flax, and hemp workers.

bystander exposure: Liability of members of the general public to come in contact with substances arising from operations or processes carried out by other individuals in their vicinity.

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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

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