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Priority Substances List Assessment Report for
2-Buthoxyethanol

Synopsis

2-Butoxyethanol is not commercially produced in Canada. It is imported for use mainly as a component of formulations, as part of consumer products or manufactured articles, and as a chemical processing aid. Most reported environmental releases are to the atmosphere, with some minor releases to water.

2-Butoxyethanol reacts with hydroxyl radicals in the air with a half-life of a few hours to about a day. Most of the 2-butoxyethanol released to the atmosphere is predicted to remain in air, with some partitioning to water and soil. 2-Butoxyethanol is biodegraded in water and soil, with an estimated half-life of 1-4 weeks. It has a low octanol/water partition coefficient and is therefore not expected to bioaccumulate to any significant degree. Only limited data are available on concentrations of 2-butoxyethanol in the environment in Canada or elsewhere.

Data on toxicity were identified for aquatic organisms, including microorganisms, invertebrates and fish. The most sensitive species reported, based on acute exposure, is the grass shrimp (Palaemonetes pugio).

Because of the limitations of environmental monitoring data, exposures for environmental compartments other than air were estimated based on modelling. Estimated environmental concentrations of 2-butoxyethanol are a few orders of magnitude less than the adverse effects thresholds calculated for sensitive organisms.

2-Butoxyethanol is not involved in stratospheric ozone depletion and is not an important contributor to climate change or ground-level ozone formation.

Based on the limited data identified, inhalation of 2-butoxyethanol in air is an important route of exposure, with estimated exposure through use of consumer products containing the substance being considerable. No data were identified concerning the contribution of food to overall exposure to 2-butoxyethanol.

Based primarily on investigations in experimental animals, the principal critical health effects associated with exposure to 2-butoxyethanol are alterations in hematological parameters associated with hemolysis. Tolerable Concentrations for these effects and for lesions of the forestomach in mice, for which information on mode of action is inadequate to preclude their relevance to humans, were developed, based on Benchmark Concentrations. A Tolerable Concentration is the level of exposure to which it is believed a person may be exposed daily over a lifetime without deleterious effect.

Levels of 2-butoxyethanol in ambient air in Canada are less than the Tolerable Concentrations derived for effects on the blood or forestomach. However, exposure to 2-butoxyethanol during use of products containing the substance could potentially exceed the Tolerable Concentrations, based on limited data on emissions from products currently available in Canada.

Based on available data, it is concluded that 2-butoxyethanol is not entering the 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; or constitute or may constitute a danger to the environment on which life depends. 2-Butoxyethanol is considered to be entering the environment in a quantity or concentration or under conditions that constitute or may constitute a danger in Canada to human life or health. Therefore, 2-butoxyethanol is considered to be "toxic" as defined in Section 64 of CEPA 1999.

Additional characterization of the ranges and distributions of concentrations of 2-butoxyethanol in consumer products currently available in Canada and their emissions is considered a clear priority as a basis for risk management.