1,1,2,2-Tetrachloroethane - 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 and 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" as defined under Section 11 of the Act may be placed on the List of Toxic Substances in Schedule I of CEPA (Subsection 33(1)). Consideration can then be given to developing guidelines, codes of practice, or regulations necessary to control any aspect of these substances' life cycle, including manufacture, use, storage, transport, and ultimate disposal.

The assessment of whether 1,1,2,2-tetrachloroethane 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.

Published data relevant to the assessment of whether 1,1,2,2-tetrachloroethane is "toxic" to the environment were obtained through on-line searches conducted in June, 1992 of the following commercial databases: Aquatic Sciences and Fisheries Abstracts (ASFA), BIOSIS, CHEMICAL ABSTRACTS, ENVIROLINE, International Register of Potentially Toxic Chemicals (IRPTC), Science Citation Index (SCI), and TOXLINE. In addition; trade information was voluntarily supplied by the chlorinated solvents industry. Data on Canadian sources, use patterns, and levels of 1,1,2,2-tetrachloroethane were emphasized. Data relevant to the environmental assessment of 1,1,2,2-tetrachloroethane obtained after January 1993 were not considered for inclusion.

To identify toxicological data relevant to the preparation of the human health-related sections of the assessment, in April 1992, literature searches were conducted on the computerized databases TOXLINE [MEDLINE, BIOSIS, and National Technical Information Service (NTIS)], TOXLIT, EMBASE, Hazardous Substances Data Bank (HSDB), Registry of Toxic Effects of Chemical Substances (RTECS), Integrated Risk Information System (IRIS), Chemical Carcinogenesis Research Information System (CCRIS), Environmental Bibliography, ENVIROLINE, POLLUTION ABSTRACTS, Environment Canada Departmental Library Catalogue (ELIAS), AQUAREF, Canadian Research Index (MICROLOG), and the Cooperative Documents Project (CODOC). In addition, computer literature searches were conducted biweekly on the MEDLINE and TOXLINE databases to identify any references incorporated since April 1992. Data obtained after the period of peer review (i.e., September 1992) were not considered in the preparation of the health-related sections of this report.

A review of available toxicological and epidemiological data on 1,1,2,2-tetrachloroethane published by the Agency for Toxic Substances and Disease Registry (1989) and a background report on toxicokinetics and health effects prepared under contract by Global-Tox International Corporation in September 1991, were consulted in the preparation of this report.

All original scientific studies that form the basis for determining whether 1,1,2,2-tetrachloroethane is "toxic" under CEPA were critically evaluated by the following Environment Canada staff (entry, exposure, and effects on the environment) and Health and Welfare Canada staff (human exposure and effects on human health):

Environment Canada

• T. Dann
• S. Jones
• K. Kaiser
• S. Lesage
• K. Lloyd
• L. Shutt

Health and Welfare Canada

• I. Caldwell
• K. Hughes
• M.E. Meek

In this report, an overview of findings concerning 1,1,2,2-tetrachloroethane that will appear in the Canada Gazette is presented. Section 2.0 is an extended summary of the technical information that is critical to the assessment. This information is presented in greater detail in supporting documentation that is available upon request. The assessment of "toxic" under CEPA is presented in Section 3.0.

As part of the review and approvals process established by Environment Canada, the environmental portions of the Assessment Report were reviewed by Dr. P. Cammer (Cammer and Associates), Dr. D. Muir (Fisheries and Oceans), Dr. D. Singleton (National Research Council Canada), and Dr. K. Woodburn (Dow Chemical Canada Inc.). Sections related to the assessment of human exposure and health effects were peer reviewed by Dr. J. Domoradzki (Dow Chemical Company, U.S., supporting documentation only), Dr. R. Bull (Washington State University, U.S.), and BIBRA Toxicology International, U.K., and subsequently approved by the Standards and Guidelines Rulings Committee of the Bureau of Chemical Hazards of Health and Welfare Canada. The final Assessment Report was reviewed and approved by the Environment Canada/Health and Welfare Canada CEPA Management Committee.

Copies of this Assessment Report and the unpublished supporting documentation 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