Guidelines for the assessment of alternatives for mine waste disposal: annex 1

Annex 1: Deleterious Substances

Section 34(1)(a) of the Fisheries Act states that a deleterious substance means:

“any substance that, if added to any water, would degrade or alter or form part of a process of degradation or alteration of the quality of that water so that it is rendered or is likely to be rendered deleterious to fish or fish habitat or to the use by man of fish that frequent that water.”

To determine if a substance, such as waste rock, is deleterious, mining proponents are to use established reference and guidance methods. These methods include, but are not limited to:

  • the Prediction Manual for Drainage Chemistry from Sulphidic Geologic Materials, 2009 (MEND Report1.20.1);
  • the Global Acid Rock Drainage (GARD) Guide, available on the “Mine Environment Neutral Drainage” website; and
  • Draft Guidelines and Recommended Methods for the Prediction of Metal Leaching and Acid Rock Drainage (Price W.A., 1997), available from the BC Ministry of Employment & Investment, Energy and Minerals Division.

These reference documents identify key characteristics of the substance in question, which help Environment Canada determine whether or not the substance should be considered deleterious. These characteristics include the substance’s potential for: generating acid; leaching metal; and releasing non-metals and compounds that are of concern, specifically for ammonia, cyanide, arsenic, selenium and total suspended solids in a mining context, and the likely concentration, chemical speciation, and relevant site-specific conditions which would inform the determination of whether the substance is deleterious.

The concentration of all other non-regulated materials (e.g., oil, grease and mill processing chemicals) must also be managed so that there are no deposits of deleterious substances into water frequented by fish.

For the purposes of illustration, the following list shows a range of deleterious substances that are managed through regulations under subsection 36(3) of the Fisheries Act.

  • Arsenic
  • Copper
  • Cyanide
  • Lead
  • Nickel
  • Zinc
  • Total suspended solids
  • Radium 226
  • Any acutely lethal effluent
  • Biochemical oxygen demanding matter
  • Total suspended matter or solids
  • Oil and grease
  • Phenols
  • Sulfide
  • Ammonia nitrogen
  • Any substance capable of altering the pH of liquid effluent or once-through cooling water
  • Mercury
  • Un-ionized ammonia
  • Total residual chlorine
  • Fish toxicants


Source: Metal Mining Effluent Regulations, Pulp and Paper Effluent Regulations, Fish Toxicant Regulations, Petroleum Refinery Liquid Effluent Regulations, Potato Processing Plant Liquid Effluent Regulations, Chlor-alkali Mercury Liquid Effluent Regulations, and the proposed Wastewater System Effluent Regulations



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