Toxicology Glossary - E
ecogenetics: Study of the influence of hereditary factors on the effects of xenobiotics on individual organismsPS pharmacogenetics, toxicogenetics
RT polymorphism
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
IPCS, 1978
ecosystem: Grouping of organisms (micro-organisms, plants, animals) interacting together, with and through their physical and chemical environments, to form a functional entity
IPCS, 1978
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 SN pheromone
ectoparasiticide: Substance intended to kill parasites living on the exterior of the host
IRIS, 1986
eczema: Acute or chronic skin inflammation with erythema, papules, vesicles, pustules, scales, crusts or scabs, alone or in combination, of varied aetiology
edema: See SN oedema
effective concentration (EC): Concentration of a substance that causes a defined magnitude of response in a given system: EC50 is the median concentration that causes 50 % of maximal response
RT lethal concentration
effective dose (ED): Dose of a substance that causes a defined magnitude of response in a given system: ED50 is the median dose that causes 50 % of maximal response
BT dose
RT lethal dose
effluent: Fluid, solid or gas discharged from a given source into the external environment
RT emission
elimination: Expulsion of a substance or other material from an organism (or a defined part thereof), usually by a process of extrusion or exclusion, sometimes after metabolic transformation
RT clearance
WHO, 1979
elimination half-life or half time: Period taken for the plasma concentration of a substance to decrease by half
BT biological half-life or half-time (t1/2)
eliminator (of a poison): Substance that contributes to the elimination of a poison from an organism.
embryo:
- 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
- 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
After USEPA, 1989
RT developmental toxicity, teratogenicity
emesis: Vomiting
emission: Release of a substance from a source, including discharges to the wider environment
SN discharge, effluent, release
RT immission
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
After WHO, 1989a
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
PS discharge standard
RT limit value
endemic: Present in a community or among a group of people; said of a disease prevailing continually in a region
endocrine: Pertaining to hormones or to the glands that secrete hormones directly into the bloodstream
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: may be isolated as microsomes following cell fractionation procedures
RT cytochrome P-420, cytochrome P-448, cytochrome P-450, microsome, mono-oxygenase, phase 1 reactions
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
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
After WHO, 1979
environment: Aggregate, at a given moment, of all external conditions and influences to which a system under study is subjected
ISO, 1975
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
PS environmental medicine, environmental hygiene
RT occupational hygiene
After WHO, 1989a
environmental health impact assessment: Estimate of the adverse health effects 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.
IPCS, 1978
environmental hygiene: 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
After WHO, 1979
SN environmental sanitation
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)"
RT environmental impact statement
environmental impact statement (EIS): Report resulting from an environmental impact assessment
RT environmental impact assessment
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.
RT biological effect monitoring, biological monitoring, reference value
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". Unlike an environmental quality standard, the EQO is usually expressed in qualitative and not quantitative terms
RT environmental quality standard
environmental quality standard (EQS): 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
SN ambient standard
RT limit value
environmental sanitation: See SN environmental hygiene
environmental transformation: Chemical transformation of substances resulting from interactions in the environment
enzootic: Present in a community or among a group of animals; said of a disease prevailing continually in a region
epidemiology: Study of the distribution and determinants of health-related states or events in populations and the application of this study to control of health problems
Last, 1988
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: the genotype is unaffected by such a change but the phenotype is altered
RT mutation, phenotype, transformation, tumour
epileptiform: Occurring in severe or sudden spasms, as in convulsion or epilepsy
epithelioma: Any tumour derived from epithelium
NT carcinoma
epithelium: Cells covering the internal and external surfaces of the body
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.
Nagel et al. (eds), 1991
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
RT aerodynamic diameter
ISO, 1979
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. The EDI is expressed in mg residue per person
WHO, 1989b
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
IRIS, 1986
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. The EMDI is expressed in mg residue per person
WHO, 1989b
etiology: See aetiology
eukaryote: Cell or organism with the genetic material packed in a membrane-surrounded structurally discrete nucleus and with well-developed cell organelles. The term includes all organisms except archaebacteria, eubacteria and cyanobacteria (until recently classified as cyanophyta or blue-green algae)
AN prokaryote
Nagel et al. (eds), 1991
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
BT risk
RT hazard
IRIS, 1986
excess rate: See SN 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 more or less inert substance added to a drug to give suitable consistency or form to the drug
RT vehicle
excretion: Discharge or elimination of an absorbed or endogenous substance, or of a waste product, and/or their metabolites, through some tissue of the body and its appearance in urine, faeces, or other products normally leaving the body. Excretion of chemical compounds from the body occurs mainly through the kidney and the gut. Volatile compounds may be largely eliminated by exhalation. Excretion by perspiration and through hair and nails may also occur. Excretion by the gastrointestinal tract may take place by various routes such as the bile, the shedding of intestinal cells and transport through the intestinal mucosa
After WHO, 1989a
RT clearance, elimination
excretion rate: Amount of substance (and/or its metabolites) or fraction that is excreted per unit time. It should be noted that according to this definition excretion does not include the passing of a substance through the intestine without absorption. When discussing the total amount of a substance in faeces (including the unabsorbed part), it is preferable to speak about faecal substance content (mol/kg) or mass content (kg/kg)
exogenous: Resulting from causes or derived from materials external to an organism
AN endogenous
exogenous substance: See SN xenobiotic.
experimental model ecosystem: See SN microcosm.
explant: Living tissue removed from its normal environment and transferred to an artificial medium for growth
exposed: Subject to a factor that is under study in the environment, for instance an environmental hazard
AN non-exposed, unexposed.
exposed group (sometimes abbreviated to exposed) in epidemiology: Group whose members 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
Last, 1988
exposure:
- 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 substance concentration, duration, and frequency (for chemical agents and micro-organisms) or intensity (for physical agents such as radiation)
- Process by which a substance becomes available for absorption by the target population, organism, organ, tissue or cell, by any route
RT risk assessment
exposure control: See BT emission and exposure control
exposure-effect relationship: See NT concentration-effect relationship, dose-effect relationship
exposure limit: General term defining an administrative substance concentration or intensity of exposure that should not be exceeded
IPCS, 1978
RT discharge limit
exposure ratio: In a case control study, value obtained by dividing the rate at which persons in the case group are exposed to the risk factor (or to the 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
After Last, 1988
exposure-response relationship: See RT concentration-response relationship, dose-response relationship
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
RT biological monitoring, biological assessment of exposure
IRPTC, 1982
external validity: Generalizability of the results of a particular study, beyond the limits of the population actually studied
BT validity
IPCS, 1978
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
IRIS, 1986
BT risk
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. The mass content is expressed in milligrams of pesticide residue or contaminant per kilogram of commodity
After Codex Alimentarius Commission, 1986
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: 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