Page 2: Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Formaldehyde


Available data on formaldehyde concentrations in drinking water indicate that intake of formaldehyde from this source is well below the level at which adverse health effects may occur. It is therefore not considered necessary to establish a maximum acceptable concentration (MAC) for formaldehyde in drinking water.

Identity, Use and Sources in the Environment

Formaldehyde is a colourless, flammable gas with a pungent, suffocating odour. It is soluble in water, acetone, benzene, diethyl ether, chloroform and ethanol. It is very reactive and condenses with numerous compounds to produce methylol or methylene derivatives. Formaldehyde is also photodegradable.Footnote 2 Formaldehyde has a log Kow of 0.35 and a Henry's law constant of 3.27 × 10-7atm·m3/mol.Footnote 3

Formaldehyde is used in the manufacture of plastics and resins, for the production of intermediates and for other miscellaneous uses, such as chelating agents. Formaldehyde-based resins and plastics accounted for over 60% of formaldehyde use in the United States in 1978. Urea-formaldehyde resins (>25% of total formaldehyde-based resins) are used principally as adhesives in the manufacture of particleboard, fibreboard and plywood. Phenolic, melamine and polyacetal formaldehyde-based resins are used as adhesives in plywood, surfacing coatings, molding compounds, thermo-setting resins in laminates and other products, such as plastic plumbing fixtures.Footnote 1,Footnote 4 Formaldehyde is also used as a disinfectant in many human medicines and cosmetics, as an antiseptic in veterinary drugs and biologicals and in fungicides, textiles and embalming fluids.Footnote 1,Footnote 5 Formaldehyde occurs in air as a product of the natural photo-oxidation of atmospheric hydrocarbons emitted in automobile, truck and aircraft exhausts.Footnote 1Automobile exhaust has been reported to account for much of the formaldehyde present in the atmosphere.Footnote 1,Footnote 6 Combustion processes in power plants, manufacturing facilities, incinerators and petroleum refineries are also sources of formaldehyde emissions.Footnote 1

Formaldehyde may be released in indoor air from urea-formaldehyde foam insulation or from particle-board that uses adhesives containing urea-formaldehyde resins.Footnote 1 Formaldehyde has been reported in industrial and municipal aqueous effluents resulting from chemical, oil and coal processing, resin production and the manufacture and use of resin glues.Footnote 1 Formaldehyde biodegrades rapidly in water, and, since it can be readily degraded by bacteria in the soil, bioaccumulation does not occur.Footnote 1,Footnote 7

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