Priority Substances List Assessment Report for Formaldehyde

Synopsis

In Canada, formaldehyde is used primarily in the production of resins and fertilizers and for a variety of minor uses. The Canadian domestic demand for formaldehyde was 191 000 tonnes in 1996.

Formaldehyde enters the Canadian environment from natural sources (including forest fires) and from direct human sources, such as automotive and other fuel combustion and industrial on-site uses. Secondary formation also occurs, by the oxidation of natural and anthropogenic organic compounds present in air. Although there are no quantitative estimates, releases from natural and secondary sources in Canada are likely greater than direct human releases. However, the highest concentrations measured in the environment occur near anthropogenic sources; these are of prime concern for the exposure of humans and other biota. Motor vehicles, the largest direct human source of formaldehyde in the Canadian environment, released an estimated 11 284 tonnes into the air in 1997. The amount of formaldehyde released into the Canadian environment from industrial processes was 1424 tonnes in 1997.

When formaldehyde is released to or formed in air, most of it will undergo various degradation processes in air, and a very small amount will move into water. When formaldehyde is released into water, it does not move into other media but is broken down in the water. Formaldehyde does not persist in the environment, but its continuous release and formation can result in chronic exposure of biota near sources of release and formation.

Extensive recent data are available for concentrations of formaldehyde in air at industrial, urban, suburban, rural and remote locations in Canada. Data for concentrations in water are limited to surface water from four rivers, effluents from industrial plants and groundwater from three industrial sites and six cemeteries. Environmental toxicity data are available for a wide range of terrestrial and aquatic organisms.

Based on the maximum concentrations measured in air, surface water, effluents and groundwater in Canada, and on the Estimated No-Effects Values derived from experimental data for terrestrial and aquatic biota, formaldehyde is not likely to cause adverse effects on terrestrial or aquatic organisms.

Formaldehyde is not involved in the depletion of stratospheric ozone or in climate change. Because of its photoreactivity and its relatively high concentrations in Canadian cities, formaldehyde plays a role in the photochemical formation of ground-level ozone.

Critical health effects in mammals associated with exposure to formaldehyde occur primarily at the site of first contact (i.e., the respiratory tract following inhalation and the gastrointestinal tract following ingestion) and are related to concentration in the relevant medium, rather than to total intake. The focus of the human health assessment is airborne exposure, due primarily to the lack of representative data on concentrations in media other than air and limited data on effects following ingestion.

Sensory irritation of the eyes and respiratory tract by formaldehyde has been observed consistently in clinical studies and epidemiological surveys in occupational and residential environments. At concentrations higher than those generally associated with sensory irritation, formaldehyde may also contribute to the induction of generally small, reversible effects on lung function.

Following inhalation in laboratory animals, formaldehyde causes degenerative non-neoplastic effects and nasal tumours in rats.

Both sustained cellular proliferation and interaction with genetic material likely contribute to induction of these tumours, and, under similar conditions, formaldehyde is considered to present a carcinogenic hazard to humans.

The majority of the population is exposed to airborne concentrations of formaldehyde less than those associated with sensory irritation. However, in some indoor locations, concentrations may approach those associated with eye and respiratory tract sensory irritation in humans. Based on comparison of risks of cancer estimated on the basis of a biologically motivated case-specific model with calculated exposure in air of the general population in Canada, priority for investigation of options to reduce exposure on the basis of carcinogenicity is considered to be low.

Based on the information available, it is concluded that formaldehyde is not entering the Canadian environment in a quantity or concentration or under conditions that have or may have an immediate or long-term harmful effect on the environment or its biological diversity. Formaldehyde is entering the Canadian environment in a quantity or concentration or under conditions that constitute or may constitute a danger to the environment on which life depends and a danger in Canada to human life or health. Therefore, formaldehyde is considered "toxic" as defined in Section 64 of the Canadian Environmental Protection Act, 1999 (CEPA 1999).

Formaldehyde contributes to the photochemical formation of ground-level ozone. It is recommended that key sources of formaldehyde be addressed, therefore, as part of management plans for volatile organic chemicals that contribute to the formation of ground-level ozone. While indications are that concentrations currently in air and water are not causing environmental harm to biota, continued and improved monitoring at sites likely to release formaldehyde is desirable, notably with regards to industrial uses for resins and for fertilizers as well as releases from pulp and paper mills.

It is also recommended that continued investigation of options to reduce exposure to formaldehyde in indoor air be considered under the authority of acts other than CEPA 1999 as part of an overall program to reduce exposure to other aldehydes (e.g., acrolein, acetaldehyde) in indoor air deemed to be "toxic" under Paragraph 64(c) of CEPA 1999.