• Abiotic Degradation

    The decomposition of a material in the environment by chemical processes, e.g., photolysis, hydrolysis and oxidation, rather than by micro-organisms, cf. biodegradation.

  • Abiotic Resources

    Resources originating from non-living sources, including soil and minerals (LCA usage).

  • Absorption

    The penetration of one substance into the inner structure of another substance, cf., adsorption.

  • Abuse

    Wrong, ill-judged or excessive use; can be applied to a range of products, foodstuffs, chemicals and pharmaceuticals, in particular alcohol and drugs.

  • Acceptable Daily Intake

    The amount of a food additive in mg/kg body weight to which an average person may be exposed daily without incurring any adverse effects; proposed by the Joint FAO and WHO Expert Committee on Food Additives (JECFA).

  • Accumulation

    Process resulting in the concentration of a substance in living organisms further to its transfer from a primary environmental compartment (as air, water, soil or sediment).


    The American Conference of Governmental Industrial Hygienists (US). The organisation is engaged in a number of occupational safety and health programmes, including the publication of Threshold Limit Values (TLVs).

  • Acidification

    The deposition of primary sulphur and nitrogen compounds as acids; these may have the potential to adversely affect the environment (LCA usage), due to their corrosive quality. A lowering of pH by addition of chemicals that generate hydrogen ions (H+) in solution.

  • Acute

    Single or short-lived, possibly severe, cf. chronic.

  • Acute Effect

    An adverse effect that occurs immediately or shortly after a single exposure.

  • Acute Toxicity

    The adverse effect resulting from a brief or single exposure to a material.

  • Adaptation to Technical Progress

    The modification of the technical aspects of an existing Directive or Regulation, generally by the adoption of a new Directive or Regulation, following the recommendations of a Committee of Adaptation established for that purpose, e.g., 'Commission Directive 90/492/EEC of 5 September 1990 adapting to technical progress for the second time Council Directive 88/379/EEC on the approximation of laws, regulations and administrative provisions of the Member States relating to the classification, packaging and labelling of dangerous preparations' (EEC/EU usage).

  • Additive(s)

    A generic name for a wide range of materials that may be added, usually in low concentrations, to stabilise or improve the performance of other products.

  • ADI

    Acceptable Daily Intake.

  • Adjuvant

    Auxiliary substance added to assist any specific process, e.g., in the production of plastics; see coadjuvant.

  • ADN

    Accord européen relatif au transport international des marchandises Dangereuses par voie de Navigation intérieure (European Agreement concerning the International Carriage of Dangerous Goods by Inland Waterways).

  • ADNR

    Accord européen relatif au transport international de marchandises Dangereuses par voie de Navigation intérieures sur le Rhin (Agreement on the carriage of dangerous substances on the Rhine).

  • ADR

    Accord européen relatif au transport de marchandises Dangereuses par Route (European Agreement concerning the International Carriage of Dangerous Goods by Road).

  • Adsorption

    The attraction of the atoms, ions or molecules of a gas or liquid to the surface of another substance, cf. absorption.

  • Advection

    Transfer or transport of a material in a fluid medium, e.g., air or water, as a result of, and in the same direction as, the flow of the fluid, cf. diffusion or partition.

  • Aerosols

    Liquid droplets or solid particles dispersed and suspended in air, e.g., as a mist or smoke.


    Association Française de Normalisation; a French organisation responsible for planning, drafting and marketing technical standards.

  • AICS

    Australian Inventory of Chemical Substances.

  • Air Monitoring

    The measurement of airborne concentrations of materials, usually contaminants.

  • Alarie Test

    A laboratory study conducted on mice as an indirect measure of upper airway sensory irritation.

  • Alcohol Type Foams

    Fire fighting foams developed for use with highly flammable water-soluble substances; have less mechanical strength than other foams and must be applied with care.

  • Aliphatics

    Hydrocarbons having straight and/or branched paraffinic structures, including alkanes, alkenes and alkynes. Practically, in the Hydrocarbon solvents industry, Aliphatics definition is wider covering: straight and/or branched paraffins, cycloparaffins and may contain limited amounts of aromatic compounds.

  • Alkanes

    Saturated hydrocarbons with the general formula CnH2n+2, paraffins.

  • Alkenes

    Unsaturated hydrocarbons containing one or more double carbon-carbon bonds in their molecules, olefins.

  • Alkynes

    Unsaturated hydrocarbons containing one or more triple carbon-carbon bonds in their molecules, acetylenes.

  • Allergen

    A material capable of stimulating an allergy.

  • Allergy

    An exaggerated susceptibility to a material which is without effect for the majority of individuals.

  • Amendment

    The modification of the operation of an existing Directive or Regulation, generally by the adoption of a new Directive or Regulation, e.g., 'Council Directive 92/32/EEC of 30 April 1992 amending for the seventh time Directive 67/548/EEC on the approximation of laws, regulations and administrative provisions relating to the classification, packaging and labelling of dangerous substances' (EEC/EU usage). More generally, the modification of any existing law or regulation at national or supranational level.

  • Ames Test

    A screening test using strains of bacteria to determine whether a chemical has mutagenic effects.

  • Anaerobe

    A micro-organism that survives without oxygen, may require absence of oxygen (obligate anearobe).

  • Anaerobic

    Taking place in the absence of atmospheric oxygen.

  • Anthropogenic

    Produced or caused by man.

  • Appearance

    The physical state (solid, liquid or gas) and the colour of the substance or preparation as supplied.

  • Aromatics

    Hydrocarbons containing alternating single and double carbon-carbon bonds one or more unsaturated usually in cyclic structured molecules, e.g. benzene, toluene or xylene, cf. aliphatics. 

  • Article

    An object which during production is given a special shape, surface or design, which determines its function to a greater degree than does its chemical composition.

  • Aspiration

    The accidental or deliberate drawing of a liquid or solid into the lungs.

  • Aspiration Hazard

    The risk of a potentially severe inflammatory response in the respiratory system following the aspiration of a liquid or solid, during accidental or deliberate ingestion or vomiting.

  • ASTM

    The American Society for Testing and Materials (US). The organisation devises consensus standards for materials characterisation and use.

  • Atrophy

    The arrested development, or wasting away, of cells or tissues.

  • Auto-ignition Temperature

    The lowest temperature at which a flammable gas or vapour/gas mixture will ignite from its own heat or from contact with a heated surface without the necessity of a spark or flame. Vapours and gases will spontaneously ignite at lower temperatures in oxygen than in air. Auto-ignition temperatures may be influenced by the presence of other substances.

  • Avian

    Pertaining to birds.