Synopsis 1,3-Butadiene is a product of incomplete combustion resulting from natural processes and human activity. While 1,3-butadiene is not persistent, it is ubiquitous in the urban environment because of its widespread combustion sources. The highest atmospheric concentrations have been measured in air in cities and close to an industrial source. Given its sources of entry into the environment, its environmental fate and concentrations measured in Canada, the environmental assessment focussed on assessing the potential risks to aquatic life, terrestrial plants, terrestrial wildlife and soil invertebrates. The potential risks were assessed assuming worst-case, hyperconservative conditions.
Analyses indicate that environmental biota are unlikely to be at risk even under such conditions.
The general population in Canada is exposed to 1,3-butadiene primarily through ambient and indoor air. Inhaled 1,3-butadiene is carcinogenic in both mice and rats, inducing tumours at multiple sites at all concentrations tested in all identified studies. In addition, 1,3-butadiene is genotoxic in both somatic and germ cells of rodents. The greater sensitivity in mice than in rats to induction of these effects by 1,3-butadiene is likely related to species differences in metabolism to active epoxide metabolites. 1,3-Butadiene also induced adverse effects in the reproductive organs of female mice at relatively low concentrations.