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2001-03-24 - Canada Gazette Part I, Vol. 135 No. 12

Publication of Final Decision on the Assessment of a Substance — N,N-Dimethylformamide — Specified on the Priority Substances List (Subsection 77(6) of the Canadian Environmental Protection Act, 1999)

Whereas a summary of a report of the assessment of N,N-dimethylformamide, a substance specified on the Priority Substances List, is annexed hereby,

Notice therefore is hereby given that the Ministers of the Environment and of Health propose to take no further action in respect of the said substance.

DAVID ANDERSON

Minister of the Environment

ALLAN ROCK

Minister of Health

Annex

Summary of the Report of the Assessment of the Substance N,N-Dimethylformamide Specified on the Priority Substances List

N,N-dimethylformamide (DMF) is a colourless liquid at room temperature and has a high water solubility and low vapour pressure.

Canadian production capacity is estimated at less than 10 000 tonnes per year. The majority produced in and imported into Canada is subsequently exported, with the total domestic demand in the range of less than 1 000 tonnes per year. The oil and gas/petrochemical sector reportedly accounted for 22 percent of the total reported quantity used in Canada during 1996, primarily for gas stream separation. During the same year, the formulation of pesticides accounted for approximately 66 percent of the DMF reportedly used in Canada. These uses are regulated under the Pest Control Products Act.

DMF appears to enter the Canadian environment primarily from industrial releases to air. In 1996, about 16 tonnes were reportedly released to the environment from various industrial locations in Canada. Of this total, 15 tonnes were released to air and less than 1 tonne was released directly into surface water. The available information suggests that spills of DMF during use, storage or transport are not a significant route of entry to the environment.

Because of the complete solubility of DMF in water, it is expected that some DMF can be transported from air to surface water or soil (pore water) in precipitation. Atmospheric photooxidation is estimated to take place over a period of days. Releases to water or soil are expected to be followed by relatively rapid biodegradation (half-life 18-36 hours). Abiotic degradation processes and sorption to soil are expected to be minimal.

No data on concentrations in ambient air or surface water in Canada were identified, and data on DMF concentrations in Canadian soil and groundwater are very limited. However, as most DMF is reported to be released to air and as little transfer to water and soil is expected, this assessment has focused on the potential effects on terrestrial organisms exposed by contact with contaminated air. The highest levels of DMF in air are assumed to be found in the immediate vicinity of the industrial facility with the greatest reported annual releases. A conservative estimate of concentrations near this point source provides an Estimated Exposure Value that is generally higher than or comparable to measurements recorded in other countries.

Environmental toxicity data are available for a range of terrestrial and aquatic organisms. Based on a comparison of the highest estimated concentration in air with the estimated no-effects concentration derived from experimental data for terrestrial biota, it is unlikely that organisms are exposed to harmful levels of DMF in the Canadian ambient environment.

DMF is not involved in the depletion of stratospheric ozone. Because of its reactivity and the relatively small amounts of DMF released to the atmosphere, it is not expected to play a role in climate change or ground-level ozone formation.

Quantitative data on concentrations of DMF in drinking water, food, indoor air or ambient air in Canada were not identified. Air in the vicinity of point sources appears to be the greatest potential source of exposure of the general population to DMF. Based on the results of epidemiological studies of exposed workers and supporting data from a relatively extensive database of investigations in experimental animals, the liver is the critical target organ for the toxicity of DMF. Worst-case estimates of exposure in the immediate vicinity of the largest emitter in Canada, which are likely 10- to 100-fold greater than those anticipated under most conditions, do not appreciably exceed a Tolerable Concentration derived on the basis of increases in serum hepatic enzymes in exposed workers. A Tolerable Concentration is the level to which it is believed a person may be exposed daily over a lifetime without deleterious effect.

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

The evaluation of options under CEPA 1999 to reduce exposure to DMF is not considered to be a priority at this time. However, this is based upon current use patterns; thus, future releases of this compound should continue to be monitored to ensure that exposure does not increase to any significant extent.

The full Assessment Report may be obtained from the Priority Substances List Assessment Report Page (www.ec.gc.ca/cceb1/eng/final/index_e.html) or from the Inquiry Centre, Environment Canada, Hull, Quebec K1A 0H3 (1-800-668-6767).