IUPAC Glossary of Terms Used in Toxicology - Terms Starting with D
Estimate of the proportion of a population which dies during a specified period. The numerator is the number of persons dying during the period; the denominator is the size of the population, usually estimated as the mid-year population. The death rate in a population is generally calculated by the formula:
10n (Number of deaths during a specified period) / (Number of persons at risk of dying during the period)
where n is usually either 3 or 5 giving rates per 1 000 or per 100 000 people in the population studied.
Note 1: This rate is an estimate of the person-time death rate, the death rate per 10n person-years: usually n = 3. If the rate is low, it is also a good estimate of the cumulative death rate.
Note 2: This term is sometimes described as the crude death rate
Unit of perceived air quality: air on mountains or the sea has a decipol = 0.01; city air with moderate air pollution has a decipol = 0.05- 0.03; acceptable indoor air quality has decipol = 1.4 (for 80% satisfaction).
Explicit pathophysiological changes following compensation for adverse effects.
Process of rendering harmless (by neutralization, elimination, removal etc.) a potentially toxic substance in the natural environment, laboratory areas, the workplace, other indoor areas, clothes, food, water, sewage etc.
Substance used for removal of leaves by its toxic action on living plants.
Enzyme which catalyses oxidation of compounds by removing hydrogen.
de minimis risk
See risk de minimis
- Addition of methanol, acetone or other suitable chemical(s) to alcohol to make it unfit for drinking.
- Change in molecular structure of proteins so that they cannot function normally, often caused by splitting of hydrogen bonds following exposure to reactive substances or heat.
Tooth enamel malformations due to excessive fluoride exposure during dental development.
deoxyribonucleic acid, DNA
Constituent of chromosomes which stores the hereditary information of an organism in the form of a sequence of purine and pyrimidine bases: this information relates to the synthesis of proteins and hence it is a determinant of all physical and functional activities of the cell, and consequently of the whole organism.
deoxyribonucleic acid (DNA) repair
Restoration of the molecular structure of DNA after it has been damaged by a chemical or physical agent: this may involve direct DNA damage reversal, base excision repair, nucleotide excision repair, mismatch repair, or double-strand break repair
- A psychic craving for a drug or other substance which may or may not be accompanied by a physical dependency.
- Reliance on a drug or other substance to maintain health.
Substance causing loss of hair.
- Process by which a substance arrives at a particular organ or tissue site, for example the deposition of particles on the ciliated epithelium of the bronchial airways.
- Process by which a substance sediments out of the atmosphere or water and settles in a certain place.
Skin reaction resulting from a single or multiple exposure to a physical or chemical entity at the same site, characterized by the presence of inflammation; it may result in cell death.
Inflammation of the skin: contact dermatitis is due to local exposure and may be caused by irritation, allergy or infection.
Study of the occurrence of disease or other health-related characteristics in populations, including general observations concerning the relationship of disease to basic characteristics such as age, sex, race, occupation, and social class; it may also be concerned with geographic location. The major characteristics in descriptive epidemiology can be classified under the headings: individuals, time and place.
Suppression of sensitivity of an organism to an allergen to which the organism has been exposed previously.
- Drying agent.
- In agriculture, a substance used for drying up plants and facilitating their mechanical harvesting.
Opposite of adsorption; a decrease in the amount of adsorbed substance.
Shedding of an outer layer of skin in scales or shreds.
- Process, or processes, of chemical modification which make a toxic molecule less toxic.
- Treatment of patients suffering from poisoning in such a way as to promote physiological processes which reduce the probability or severity of adverse effects.
Estimated measure of the expected harm or loss associated with an adverse event, usually in a manner chosen to facilitate meaningful addition over different events. It is generally the integrated product of arbitrary values of risk and hazard and is often expressed in terms such as costs in US dollars, loss in expected years of life or loss in productivity, and is needed for numerical exercises such as cost-benefit analysis.
Adverse effects on the developing organism (including structural abnormality, altered growth, or functional deficiency or death) resulting from exposure through conception, gestation (including organogenesis), and postnatally up to the time of sexual maturation.
diarrheic shellfish poisoning, DSP
diarrheal shellfish poisoning
Serious illness which is a consequence of consumption of bivalve shellfish (mollusks) such as mussels, oysters and clams that have ingested, by filter feeding, large quantities of micro-algae containing a group of high molecular weight polyethers such as okadaic acid, dinophysis toxins, pectenotoxins, and yessotoxin; gastroenteritis develops shortly after ingestion and generally lasts 1-2 days.
Spontaneous differential movement of components in a system.
Note: In molecular terms, the driving force for diffusion is random thermal motion. In thermodynamic terms, the driving force is a gradient of chemical potential.
Chromosome state in which the chromosomes are present in homologous pairs.
Note: Normal human somatic (non-reproductive) cells are diploid (they have 46 chromosomes), whereas reproductive cells, with 23 chromosomes, are haploid.
discharge (effluent, emission) standard or release
Maximum amount of a pollutant released from a given source to a specified medium which is acceptable under specified circumstances.
See intermittent effect
Any difference in a character between individuals due to genetic differences such as may occur in dizygotic twins, or between matched pairs in a case cohort study.
Literally, dis-ease, lack of ease; pathological condition that presents a group of symptoms peculiar to it and which establishes the condition as an abnormal entity different from other normal or pathological body states.
See intermittent effect
dispersion (in environmental chemistry)
Dilution of a pollutant by spreading in the atmosphere or water due to diffusion or turbulent action.
- Natural tendency shown by an individual or group of individuals, including any tendency to acquisition of specific diseases, often due to hereditary factors.
- Total of the processes of absorption of
a chemical into the circulatory systems, distribution
throughout the body, biotransformation,
Reduction in the amount of a pesticide or other compound which has been applied to plants, soil etc. (used when it is not clear whether this is by mineralization degradation, binding, or leaching).
See area source
- Apportionment of a solute between two phases. The term
partition or extraction may also be used in this sense where
- Dispersal of a substance and its derivatives throughout the
natural environment or throughout an organism.
- Final location(s) of a substance within an organism after dispersal.
See partition ratio
Excretion of urine, especially in excess.
See deoxyribonucleic acid cloning
See deoxyribonucleic acid repair
See deoxyribonucleic acid sequencing
Allele which expresses its phenotypic effect when present in either the homozygous or the heterozygous state.
dominant lethal mutation
Genetic change occurring in a germ cell which does not cause dysfunction of the gamete but which is lethal to the fertilized egg or developing embryo which develops from it.
Note: Induction of a dominant lethal event after exposure to a chemical substance (dominant lethal test) indicates that the substance has affected germinal tissue of the test species.
- (of a substance)
Total amount of a substance administered to, taken up, or absorbed by an organism, organ, or tissue.
- (of radiation)
Energy or amount of photons absorbed by an irradiated object during a specified exposure time divided by area or volume.
Relation between dose and the magnitude of a measured biological change.
Graph of the relation between dose and the magnitude of the biological change produced measured in appropriate units.
Evaluation of materials for their potential to cause dermal or ocular irritation and corrosion following local exposure; generally using the rabbit model (almost exclusively the New Zealand White) although other animal species have been used.
Any substance which when absorbed into a living organism may modify one or more of its functions.
Note: The term is generally accepted for a substance taken for a therapeutic purpose, but is also commonly used for abused substances.
duplicate portion sampling method
duplicate diet study
Study in which test persons consume their ordinary diet but, for each meal, they prepare for subsequent analysis a duplicate portion of all food as prepared, served and consumed.
duplicate (replicate) samples (in
Two (or multiple) samples taken under the same or comparable conditions.
Imperfect articulation of speech due to neuromuscular damage.
Abnormal, impaired, or incomplete functioning of an organism, organ, tissue or cell.
Abnormal development of an organ or tissue identified by morphological examination.
Difficult or labored breathing.