Background Information on Proposed Metal Mining Effluent Regulations

Jamie Kneen

National Program Co-Lead

In 1977, the Metal Mining Liquid Effluent Regulations (MMLER) were promulgated under the Fisheries Act. In 1990, the Government of Canada announced its intention to update and strengthen the MMLER in its Green Plan, and the Aquatic Effects of Mining (AQUAMIN) process was established to review the aquatic effects of mining in Canada and make recommendations on improved regulations. In 1996, the results of a multi-stakeholder review of the Regulations were released in a report entitled "AQUAMIN: Assessment of the Aquatic Effects of Mining in Canada." A multi-stakeholder advisory process was subsequently established to "modernize" the MMLER with the goal of completing this process by 2000, with the advisory groups last meeting in June 1999. On July 28, 2001, the proposed Metal Mining Effluent Regulations were published in the Canada Gazette Part I with a 60 day comment period ending September 26, 2001. The regulations can be viewed at


Acutely Lethal Effluent: A key improvement in the regulation will be the new requirement of a non-acutely lethal effluent. If rainbow trout are exposed to undiluted effluent for 96 hours and less than half of the fish die, the effluent is considered to be not acutely lethal. However, the revised regulation will only go half the necessary distance as the requirement is only for rainbow trout and not for water fleas, Daphnia magna. Environmental representatives to the review process advised the government to adopt more stringent measures for lethality by requiring that effluent also be non-acutely lethal to the invertebrate Daphnia magna as the water fleas show the effect of pollutants on a different level of the food chain, which will eventually have an impact on fish. While mines will now be required to monitor effluent effects on Daphnia magna they are not required to produce effluent that is non-acutely lethal to Daphnia magna.

Allowable Levels of Pollutants: The proposed limits are too lenient. Other than the Total Suspended Solids limit, which was reduced from a monthly average of 25 mg/l to 15 mg/l, and the addition of an upper limit for pH of 9.5, limits for arsenic, copper, lead, nickel and zinc remain the same as they were in the original MMLER of 1977. Allowable levels for these metals are lower in the US, and the Government's own consultants (Senes Consultants Limited) recommended lower limits based on available technology. Cyanide was added to the list of regulated substances, so that gold mines using cyanide in their milling process are now included in the new regulations, bringing the total of mines covered from 30 to 93. However, other potentially toxic metals that are common in mine effluent, such as cadmium and mercury, were not added to the list of regulated metals. Finally, the limits are based on concentration rather than environmental loadings. The proposed limits will not spur technological innovation.

Environmental Effects Monitoring Linkage: The new regulations will introduce an Environmental Effects Monitoring (EEM) program. A national EEM program would allow the development of body of information based on the application of consistent monitoring criteria for which standard tools and methods have been developed. However, the regulations contain no provisions that allow findings from the EEM process to lead to improved regulations, and there is no legal tool to require site-specific regulations should monitoring results show this to be warranted.

Reporting of Toxicity Results: Monitoring data, inspection data, prosecution data, EEM data, and all other information should be easily available to the public. Environment Canada has announced an objective of annual reporting, but what is necessary - and is absent in the current draft - is a requirement within the regulations to provide the monitoring, inspection, and prosecution data, and EEM conclusions, to the public in a comprehensive and accessible fashion, and a requirement to establish a National Toxicity Registry.

Alice Arm Tailings Deposition Regulation Revoked: Deposition of mine waste that does not meet the regulations of the former MMLERs, and the proposed MMERs, into waters frequented by fish was, and remains, prohibited. The new regulations revoke provisions that allowed a site-specific exception to the MMLERs, the Alice Arm Tailings Deposition Regulation, and introduce a procedurally more difficult and more transparent process that mining companies will have to go through if they seek an exemption from the MMERs. A request to deposit waste that does not meet MMER standards into waters frequented by fish will require Governor in Council and Cabinet approval, and it will need to be put under Schedule Two of the new regulations. This will require an amendment to the regulations, which will have to go through Gazette One and Two. Such an amendment will also trigger the Canadian Environmental Assessment Act and provincial Environmental Assessment processes.