Priority Substances List Assessment Report for 2-Methoxyethanol

1.0 Introduction

The Canadian Environmental Protection Act, 1999 (CEPA 1999) requires the federal Ministers of the Environment and of Health to prepare and publish a Priority Substances List (PSL) that identifies substances, including chemicals, groups of chemicals, effluents and wastes, that may be harmful to the environment or constitute a danger to human health. The Act also requires both Ministers to assess these substances and determine whether they are "toxic" or capable of becoming "toxic" as defined in Section 64 of the Act, which states:

...a substance is toxic if it is entering or may enter the environment in a quantity or concentration or under conditions that

1. have or may have an immediate or long-term harmful effect on the environment or its biological diversity;
2. constitute or may constitute a danger to the environment on which life depends; or
3. constitute or may constitute a danger in Canada to human life or health.
   

Substances that are assessed as "toxic" as defined in Section 64 may be placed on Schedule I of the Act and considered for possible risk management measures, such as regulations, guidelines, pollution prevention plans or codes of practice, to control any aspect of their life cycle, from the research and development stage through manufacture, use, storage, transport and ultimate disposal.

Based on initial screening of readily accessible information, the rationale for assessing 2-methoxyethanol (along with 2-ethoxyethanol and 2-butoxyethanol) provided by the Ministers' Expert Advisory Panel on the Second Priority Substances List (Ministers' Expert Advisory Panel, 1995) was as follows:

Potential sources of exposure to these compounds include releases from various industrial and consumer uses. These compounds are widely used as solvents in paints and protective coatings; in printing inks, industrial solvents and cleaners; in the production of plasticizers; as a de-icer in fuels and automotive brake fluids; and in electronics manufacturing. Effects due to exposure include disorders of the central nervous system, blood system, kidneys and liver in both humans and animals. An assessment is required to determine the presence of these substances in the Canadian environment, exposure and the potential risks to human health.

Descriptions of the approaches to assessment of the effects of Priority Substances on the environment and human health are available in published companion documents. The document entitled "Environmental Assessments of Priority Substances under the Canadian Environmental Protection Act. Guidance Manual Version 1.0 -March 1997" (Environment Canada, 1997a) provides guidance for conducting environmental assessments of Priority Substances in Canada. This document may be purchased from:

Environmental Protection Publications
Environmental Technology Advancement Directorate
Environment Canada
Ottawa, Ontario
K1A 0H3

An electronic version (PDF file), may be requested from: PSL.LSIP@ec.gc.ca. It should also be noted that the approach outlined therein has evolved to incorporate recent developments in risk assessment methodology, which will be addressed in future releases of the guidance manual for environmental assessments of Priority Substances.

The search strategies employed in the identification of data relevant to the assessment of entry, environmental fate and exposure and potential effects on the environment (prior to October 1999) are presented in Appendix A. Review articles were consulted where appropriate. However, all original studies that form the basis for determining whether 2-methoxyethanol is "toxic" under Paragraph 64(a) or 64(b) of CEPA 1999 have been critically evaluated by staff of Environment Canada.

The approach to assessment of effects on human health is outlined in the following publication of the Safe Environments Program (formerly the Environmental Health Directorate) of Health Canada: "Canadian Environmental Protection Act - Human Health Risk Assessment for Priority Substances" (Health Canada, 1994), copies of which are available from:

Existing Substances Division
Health Canada
Environmental Health Centre
Tunney's Pasture
Address Locator 0801C2
Ottawa, Ontario
K1A 0L2

or on the Safe Environments Program (formerly the Environmental Health Directorate) publications web site (www.hc-sc.gc.ca/hecs-sesc/exsd/ psap.htm). The approach is also described in an article published in the Journal of Environmental Science and Health -Environmental Carcinogenesis & Ecotoxicology Reviews (Meek et al., 1994). It should be noted that the approach outlined therein has evolved to incorporate recent developments in risk assessment methodology, which are described on the Existing Substances Division web site (www.hc-sc.gc.ca/exsd-dse) and which will be addressed in future releases of the approach paper for the assessment of effects on human health.

The approach to assessment of 2-methoxyethanol is necessarily restricted because of the extremely limited data upon which to base estimates of population exposure. Moreover, use of this substance has declined substantially worldwide in recent years, as it has been replaced with less hazardous substances. Indeed, available information indicates that 2-methoxyethanol has not been produced in Canada in the last several years. Therefore, in view of the fact that measures have been introduced to reduce population exposure, a screening approach has been adopted for assessment of whether or not the substance would be considered "toxic" under Paragraph 64(c) of CEPA 1999 primarily as a basis for determining whether current measures are sufficiently protective of human health.

In view of the limited objectives of this screening assessment, therefore, lowest effect levels identified primarily from secondary sources are compared with worst-case or bounding estimates of exposure. The adequacy of these rather crude margins of exposure is considered in relation to intake from various sources estimated on the basis of primary review of the limited available Canadian data on exposure from various sources, including environmental media and consumer products. On this basis, areas where additional information may be required to ensure that current measures for reduction of population exposure are sufficiently protective have been identified.

Data on the health effects of 2-methoxyethanol were identified primarily from a review prepared in 1996 by BIBRA International, which was updated and modified in 1998 (BIBRA International, 1996/Health Canada, 1998). Relevant data identified subsequent to this update are summarized in Health Canada (1999). The search strategies used in the identification of relevant data on health effects from 1996 to October 1999 are outlined in Appendix A.

Sections of the Assessment Report related to the environmental assessment of 2-methoxyethanol and the environmental Supporting Document (Environment Canada, 1999) were prepared or reviewed by the members of the Environmental Resource Group, established by Environment Canada to support the environmental assessment:

D. Boersma, Environment Canada
R. Breton, Environment Canada
P. Cureton, Environment Canada
N. Davidson, Environment Canada
R. Desjardins, Environment Canada
L. Hamel, Union Carbide Canada Inc.
B. Lee, Environment Canada
S. Lewis, Chemical Manufacturers' Association
B. Sebastien, Environment Canada
K. Taylor, Environment Canada (lead for the environmental assessment)

Sections of the Assessment Report relevant to the environmental assessment and the environmental Supporting Document (Environment Canada, 1999) were also reviewed by:

S. Dobson, Institute of Terrestrial Ecology
C. Staples, Assessment Technologies Inc.

The health-related sections of the Assessment Report were prepared and the background Supporting Document was updated by the following staff of Health Canada:

H. Hirtle
K. Hughes
M.E. Meek
L. Turner

Adequacy of data coverage and defensibility of the conclusions presented in the health assessment were considered in a written review by:

Dourson, Toxicology Excellence in Risk Assessment
J.B. Knaak, Oxychem (retired)
R.A. Rudel, Silent Spring Institute

The health-related sections of the Assessment Report were reviewed and approved by the Healthy Environments and Consumer Safety Branch Risk Management meeting of Health Canada.

The entire Assessment Report was reviewed and approved by the Environment Canada/Health Canada CEPA Management Committee.

A draft of the Assessment Report was made available for a 60-day public comment period (August 19 to October 18, 2000) (Environment Canada and Health Canada, 2000). Following consideration of the comments received, the Assessment Report was revised as appropriate. A summary of the comments and their responses is available on the Internet at:

www.ec.gc.ca/substances/ese/eng/psap/final/main.cfm

The text of the Assessment Report has been structured to address environmental effects initially (relevant to determination of "toxic" under Paragraphs 64(a) and (b)), followed by effects on human health (relevant to determination of "toxic" under Paragraph 64(c)).

Copies of this Assessment Report are available upon request from:

Inquiry Centre
Environment Canada
Main Floor, Place Vincent Massey
351 St. Joseph Blvd.
Hull, Quebec
K1A 0H3

or by emailing:

PSL.LSIP@ec.gc.ca

Unpublished supporting documentation, which presents additional information, is available upon request from:

Commercial Chemicals Evaluation Branch
Environment Canada
14th Floor, Place Vincent Massey
351 St. Joseph Blvd.
Hull, Quebec
K1A 0H3

or

Existing Substances Division
Health Canada
Environmental Health Centre
Tunney's Pasture
Address Locator 0801C2
Ottawa, Ontario
K1A 0L2