Common Toxicological Terminology

ABSORPTION  – The uptake of a chemical or water into or across a tissue, such as skin.

ACCUMULATION  – The build-up of chemical in the organism as a result of repeated, or long term exposure.

ACUTE TOXICITY – adverse effects arising from a single exposure or short term exposure to a chemical.

ALLERGEN – A substance which causes an allergic reaction.

ALLERGY – An adverse reaction which is caused by an over-stimulation of the immune system in response to a specific allergen, which is otherwise harmless and would be normally tolerated by the majority of those who come in contact with it.

BENIGN TUMOUR – A tumour that does not invade surrounding tissues or spread to other parts of the body.

CARCINOGEN – A substance that is capable of causing cancer.

CARCINOGENESIS – The process of the development of a cancer.

CHRONIC TOXICITY – Adverse health effects arising from continuous or intermittent exposure to low concentrations of chemical over a lifetime.

CORROSIVE  – A chemical that causes irreversible alterations or destruction in living tissue at the site of contact.

CUMULATIVE EXPOSURE  – A summation of all the exposures that have been undergone by an organism during a specified period of time.

DERMATITIS – Inflammation of the skin

DEVELOPMENTAL TOXICOLOGY – Adverse toxic effects in the developing embryo or foetus

DNEL – Derived No Effect Level. This is the dose above which exposure may give rise to adverse effects.

DOSE – The amount of chemical administered. It is a measure of exposure.

DOSE –RESPONSE – The relationship between the dose of a chemical and the degree/severity of the resulting effect.

ELIMINATION/EXCRETION – The removal of a chemical from the body. This occurs mostly via exhalation of air, or in the urine or faeces.

END POINT  – A specific biological effect or response which is used as an indicator of the effect of the chemical on the organism.

EPIDEMIOLOGY – The study of the incidence and distribution of disease in populations.

EXPOSURE – Contact with a chemical. The most common routes are inhalation, skin contact and also by oral ingestion.

GAVAGE – Oral feeding by a tube.

GENOTOXIC – Chemicals that cause hereditary mutations as a result of directly interacting with the DNA.

GENOTOXIC CARCINOGENS – Chemicals causing cancer as a result of directly interacting with DNA.

HAZARD –The inherent ability of a chemical to cause an adverse effect

HYPERSENSITIVITY – The state in which an individual reacts following exposure to a substance with allergic effects  after having been exposed (sensitised).

IN VITRO – Latin for “in glass”. Studies which use tissue, cellular or subcellular extracts from a living organism.

IN VIVO – Studies which are carried out in living organisms.

IRRITANT – A chemical causing a localised inflammatory reaction to skin or mucous membranes at the site of contact.

LC₅₀  – Lethal Concentration 50%. This is the concentration which causes death in 50% of the test population.

LIPOPHILIC – “fat loving.” This term refers to the ability of a chemical to dissolve in lipids, fats, etc.

LOAEL – Lowest Observable Adverse Effect Level.  This is the lowest dose in the study which causes an observable adverse effect.

MALIGNANT TUMOUR – A tumour which is cancerous and will metastasise into surrounding tissues.

MUTATION – An alteration in the genetic material, which can be passed onto subsequent generations.

NEOPLASM – Another word for tumour.

NEUROTOXIN – A chemical that causes adverse effects in the nervous system.

NOAEL – No Observed Adverse Effect Level. This is the largest dose in a given study that does not cause an adverse effect.

NON GENOTOXIC CARCINOGEN – Chemical carcinogens that cause cancer by effects other than direct damage to the genetic material.

PRIMARY IRRITANT – A chemical that causes an inflammatory reaction on first contact.

SENSTISATION – The immune process by which  individuals become hypersensitive to a substance to which they are exposed. Subsequent exposure can lead to the development of an allergic response.

SYSTEMIC EFFECTS – Effects which occur somewhere within the body, for example in the liver or kidney, etc.

TERATOGEN – A chemical agent causing adverse effects in the normal embryonic development without causing lethality in the foetus or maternal toxicity.

TOXICOLOGY – The study of adverse effects of chemicals on living organisms.