The Canadian Environmental Protection Act (CEPA) requires the Minister of the Environment and the Minister of Health 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
Substances that are assessed as "toxic" as defined under Section 11 may be placed on the List of Toxic Substances (Schedule I of CEPA). 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 substance "nickel and its compounds" is included on the Priority Substances List. The assessment of whether "nickel and its compounds" are "toxic", as defined under Section 11 of CEPA, was based on the determination of whether they enter or are likely to enter the Canadian environment in a concentration or quantities or under conditions that could lead to exposure of humans or other biota to levels that could cause adverse effects.
Based on the considerations that most of the nickel present in the environment occurs in inorganic form and the nature of the groups of nickel compounds considered in a recent extensive epidemiological study, assessment of "nickel and its compounds" under Paragraph 11(c) of CEPA focuses principally on metallic, "sulphidic" (including nickel subsulphide), "oxidic" (including nickel oxide, nickel-copper oxide, nickel silicate oxides, and complex oxides), and "soluble" (primarily nickel sulphate and nickel chloride) nickel compounds. Due to lack of relevant data, it has not been possible to assess individual nickel compounds within these groups. The term "nickel" in this report refers to total inorganic nickel, unless otherwise specified.
For the determination of whether the priority substance "nickel and its compounds" is "toxic" to the environment under Paragraph 11(a), this assessment focuses on inorganic forms of nickel (since most nickel present in and entering the environment is inorganic), and particularly on dissolved forms, and those likely to be soluble over time under the range of pH and redox potential conditions that occur in the environment (since dissolved and soluble forms of nickel are expected to be most available for uptake by organisms). Although results of research on "nickel and its compounds" conducted outside Canada were considered, available Canadian data on sources, concentrations, fate, and effects on the environment were emphasized. Data relevant to the assessment of whether the priority substance, "nickel and its compounds", is "toxic" to the environment under CEPA were identified and obtained from original and review articles, books, and criteria documents published up to June 1993. These articles were obtained from searches of primary journals, as well as searches of the following abstracting services and data bases: CHEMICAL ABSTRACTS, BIOLOGICAL ABSTRACTS, POLLUTION ABSTRACTS, CURRENT CONTENTS, U.S. Environmental Protection Agency Toxic Releases Inventory, U.S. Agency for Toxic Substances and Disease Registry, MEDLINE, Canada Centre for Occupational Health and Safety-Access System (CCOHS), WAVES, AQUAREF, Aquatic Sciences and Fisheries Abstract (ASFA), AQUIRE (1978 to 1992), National Technical Information Service (NTIS), ENVIROLINE, and TOXLIT. Unpublished data were provided by the Canadian Wildlife Service, K. Winterhalder of Laurentian University in Sudbury, and P. Friske of the Geological Survey of Canada. From 1991 through 1993, background reports on the fate and concentrations of "nickel and its compounds" in the Canadian environment were prepared under contract to Environment Canada by O. Kulikovsky, H. Evans, P. Outridge, L. Evans, and M. Goss, and under contract to Natural Resources Canada by P. Doyle. Information was also obtained from the CEPA Domestic Substances List and from Statistics Canada.
For assessment of data other than those considered to be critical for determination of whether "nickel and its compounds" are "toxic" to human health under CEPA, evaluations of agencies such as the International Programme on Chemical Safety (IPCS, 1991), the U.S. Agency for Toxic Substances and Disease Registry (ATSDR, 1988; 1991), and the International Agency for Research on Cancer (IARC, 1990) have been consulted where available and considered appropriate. To identify toxicological data relevant to the preparation of the supporting documentation, a background review on the effects in experimental animals and humans was prepared under contract by BIBRA Toxicology International in 1992. Information therein was identified on the basis of a literature search of BIBRA's data sources. The following computerized data bases were also searched for relevant data in February, 1992: Hazardous Substances Data Bank (HSDB), Integrated Risk Information System (IRIS), CHEMID, Registry of Toxic Effects of Chemical Substances (RTECS), EMBASE, TOXLINE, and TOXLIT (all 1988 to 1992). Dr. G. Jenkins of the Ontario Ministry of the Environment provided monitoring data on levels of nickel in drinking water. Data relevant to assessment of whether "nickel and its compounds" are "toxic" to human health obtained after the completion of these sections of this report (i.e., August 1993) were not considered for inclusion.
Review articles were consulted where considered appropriate. However, all original studies that form the basis for the determination of "toxic" under CEPA have been critically evaluated by the following Environment Canada staff (effects on the environment) and Health Canada staff (human exposure and effects on human health):
|Environment Canada||Health Canada|
Quantitative estimates of carcinogenic potency were provided by J. Shedden and S. Bartlett of Health Canada after consultation with Dr. H.J. Gibb of the U.S. Environmental Protection Agency.
In this report, a synopsis that will appear in the Canada Gazette is presented. In addition, an extended summary of the technical information that is critical to the assessment is presented in Section 2.0. The assessment of whether "nickel and its compounds" are "toxic" under CEPA is presented in Section 3.0. Supporting documentation in which the technical information is presented in greater detail has also been prepared and is available upon request.
As part of the review and approvals process established by Environment Canada, the environmental sections of this Assessment Report were reviewed by Prof. T.C. Hutchinson, (Trent University, Peterborough, Ontario) and Prof. E. Nieboer, (McMaster University, Hamilton, Ontario). Comments on the adequacy of coverage of the literature relevant to assessment of effects on human health in the supporting documentation were invited from Dr. J.S. Warner (INCO Ltd.), Dr. Albert Cecutti (Falconbridge Ltd.), Ms. D. Sivulka (NiPERA Inc.), and Mr. G. Crawford (Nickel Development Institute). Sections of the supporting documentation relevant to human exposure were forwarded to officials of the Mining Association of Canada for identification of additional pertinent data. Following external peer review of the draft health-related sections of the supporting documentation and Assessment Report by Dr. F.W. Sunderman (University of Connecticut Medical School), Dr. H.J. Gibb (U.S. Environmental Protection Agency), Dr. H. Shannon (McMaster University Medical Centre), Dr. L. Elinson (Ontario Workers Compensation Board), Dr. R.A. Goyer (a consulting toxicologist), Dr. S.H.H. Swierenga (Science Council of British Columbia), and staff of BIBRA Toxicology International (U.K.), these sections were approved by the Standards and Guidelines Rulings Committee of the Bureau of Chemical Hazards of Health Canada. The final Assessment Report was subsequently reviewed and approved by the Environment Canada/Health Canada CEPA Management Committee.
Copies of this Assessment Report and the unpublished supporting documentation are available upon request from:
Commercial Chemicals Branch
14th Floor, Place Vincent Massey
351 St. Joseph Boulevard
Environmental Health Centre