Methyl Methacrylate - PSL1

1.0 Introduction

The Canadian Environmental Protection Act (CEPA) requires the Minister of the Environment and the Minister of National Health and Welfare to prepare and publish a Priority Substances List 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 to determine whether they are "toxic" as defined under Section 11 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:

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

Substances that are assessed as "toxic" according to Section 11 may be placed on Schedule I of the Act. Consideration can then be given to developing regulations, guidelines, or codes of practice to control any aspect of these substances' life cycle, from the research and development stage through manufacture, use, storage, transport, and ultimate disposal.

The assessment of whether methyl methacrylate (MMA) is "toxic", as defined under CEPA, was based on the determination of whether it enters or is likely to enter the Canadian environment in a concentration or quantities or under conditions that could lead to exposure of humans or other biota at levels that could cause adverse effects.

To identify the toxicological and environmental data relevant to the preparation of the Supporting Document, literature searches were conducted on the following computerized databases: Hazardous Substances Data Bank (HSDB), Registry of Toxic Effects of Chemical Substances (RTECS), Chemical Carcinogenesis Research Information System (CCRIS) (1991), Toxline (1981 to 1991), Toxlit (1989 to 1991, only), Chemistry Abstracts (1967 to 1991), Biological Abstracts (1969 to 1991), National Technical Information Service (NTIS) (1964 to 1989), Pollution and Toxicology Database (POLTOX) (1987 to 1992), Pollution Abstracts (1978 to 1989), and International Register of Potentially Toxic Chemicals (IRPTC), DIALOG, and Environmental Bibliography (to 1989). Other sources of information were identified through FATERATE (1989) and Chemical Evaluation Search and Retrieval System (CESARS) (1988). For toxicological data, searches were also conducted of the three most recent monthly editions of CURRENT CONTENTS.

To identify data relevant to the estimation of exposure of the general population to methyl methacrylate, the following databases were searched: Environment Canada Departmental Library Catalogue (Elias) (1991), AQUAREF (1970 to 1991), Canadian Research Index (MICROLOG) (1979 to 1991), Cooperative Documents Project (CODOC) (1991).

For assessment of data other than those considered to be critical for determination of whether MMA is "toxic" to the environment or human health under the Act, existing evaluations, such as those of the United States Environmental Protection Agency (U.S. EPA, 1985) and the International Agency for Research on Cancer (IARC, 1979), have been consulted where considered appropriate. The Methacrylate Producers Association also provided a report entitled "Methyl Methacrylate: A Toxicology Review" (MPA, 1991) for consideration in the preparation of the Supporting Document. Unvalidated studies of Industrial Biotest (IBT) Laboratories have been cited but not used directly in the assessment of "toxic" under CEPA.

Information was also sought from the following agencies:

• World Health Organization, Geneva, Switzerland;
• Dutch Expert Committee for Occupational Standards, Netherlands;
• Department of Toxic Substances, Ministry of Social Affairs and Employment, Netherlands;
• International Agency for Research on Cancer, Lyon, France;
• European Chemicals Industry Ecology and Toxicology Centre, Brussels, Belgium;
• Norwegian State Pollution Control Authority, Oslo, Norway; and
• United States Environmental Protection Agency (U.S. EPA).

Data relevant to the assessment of whether MMA is "toxic" to human health obtained after the completion of human health-related sections of this report (i.e., September 1992) were not considered for inclusion. Similarly, data relevant to the assessment of whether MMA is "toxic" to the environment obtained after the completion of these sections of the report (i.e., March 1992) were not considered for inclusion.

Although review articles were consulted where considered appropriate, all original studies relevant to the assessment of whether MMA is "toxic" under Section 11 of CEPA have been critically evaluated by the following Health and Welfare staff (human exposure and effects on human health) and Environment Canada staff (entry, and environmental exposure and effects):

Environment Canada
K.M. Lloyd

Health and Welfare
P.K.L. Chan
M.E. Meek
F. Wandelmaier

The human health-related sections of the Supporting Document and/or Assessment Report were reviewed externally by Dr. J. Siemiatycki, University of Quebec; Dr. N.D. Krivanek, E.I. du Pont de Nemours, Delaware (Supporting Document only), and British Industrial Biological Research Association (BIBRA) Toxicology International. These sections were then approved by the Standards and Guidelines Rulings Committee of the Bureau of Chemical Hazards of Health and Welfare Canada. As part of the review and approvals process established by Environment Canada, the environmental portions of the Assessment Report and Supporting Document were reviewed by Dr. N. Bunce, University of Guelph and Dr. N.D. Krivanek, E.I. du Pont de Nemours. The final Assessment Report was reviewed and approved by the Environment Canada/Health and Welfare Canada CEPA Management Committee.

In this report, a Synopsis is presented which will appear in the Canada Gazette. An extended summary of technical information that is critical to the assessment is presented in Section 2.0. This information is presented in greater detail in a Supporting Document which is available upon request. The assessment of whether MMA is "toxic" under CEPA is presented in Section 3.0.

Copies of this Assessment Report and the unpublished Supporting Document are available upon request from:

Commercial Chemicals Branch
Environment Canada
14th Floor, Place Vincent Massey
351 Saint-Joseph Boulevard
Hull, Quebec,
Canada
KIA 0H3

Environmental Health Centre
Room 104
Health Canada
Tunney's Pasture
Ottawa, Ontario,
Canada
K1A 0L2