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Priority Substances List Assessment Report for 2-Methoxyethanol

Synopsis

2-Methoxyethanol is not commercially produced in Canada. It is imported for use mainly as a chemical processing aid and as a component of formulated products. The use of 2-methoxyethanol has declined over the past few years because it has been partially replaced in some countries by other substances. All reported environmental releases are to the atmosphere.

2-Methoxyethanol reacts with hydroxyl radicals in the air with a half-life of about 18 hours. Much of the 2-methoxyethanol released to the atmosphere is predicted to remain in air, but a substantial proportion would partition to water and to soil. 2-Methoxyethanol is biodegraded in surface water and aerobic soil with an estimated half-life of 1-4 weeks. It is somewhat more persistent under anaerobic conditions. 2-Methoxyethanol has a very low octanol/water partition coefficient and is therefore not expected to bioaccumulate to any significant degree. There are very few available data on concentrations of 2-methoxyethanol in the environment in Canada or elsewhere.

Data on toxicity exist for aquatic organisms, including microorganisms, invertebrates and fish. 2-Methoxyethanol is not very toxic to these organisms; in a number of studies, the LC₅₀ was above the highest concentration tested.

Because of the paucity of environmental monitoring data, exposure values for the environmental assessment were estimated based on modelling. Estimated environmental concentrations of 2-methoxyethanol are several orders of magnitude lower than the adverse effects thresholds calculated for sensitive organisms.

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

Based on a relatively extensive database in experimental animals, 2-methoxyethanol has consistently been associated with a wide range of adverse effects on health, including those considered to be severe and irreversible (e.g., teratogenicity), with some occurring at relatively low levels of exposure. However, although relevant data are limited, exposure of the general population through environmental media is expected to be low, due to reported declining use of the compound in recent years as it is replaced with less hazardous compounds. Margins between worst-case estimates of exposure from environmental media and lowest effect levels for developmental toxicity obtained in toxicological investigations in experimental animals are large. However, available data are insufficient to conclude that margins between worst-case estimates of exposure in consumer products and lowest effect levels are adequate.

Based on these considerations, it is concluded that 2-methoxyethanol 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 that constitute or may constitute a danger to the environment on which life depends. On the basis principally of its high health hazard potential, 2-methoxyethanol may 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-methoxyethanol is considered to be "toxic" under Section 64 of the Canadian Environmental Protection Act, 1999 (CEPA 1999).

It is recommended that additional information be acquired on patterns of use of 2-methoxyethanol in Canada, particularly in relation to its presence in consumer products. It is further recommended that, in view of the profile of toxicity of 2-methoxyethanol, potential for exposure of the general population to this compound be eliminated or reduced to the extent possible.