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Ministry of Environment and Climate Change Strategy

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Alaska Department of Environmental Conservation

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B.C.-Alaska Transboundary Rivers Monitoring Program: final report results

The program has released its final report including the activities and results from two years of sampling – from 2017 to 2019. The sampling program included physical habitat assessments, physical and chemical analyses of water and sediment, and chemical analyses of fish and invertebrates collected in the Taku, Stikine, and Unuk watersheds.

Water and sediment samples were tested for a number of elements, such as: cadmium, copper, selenium, zinc, arsenic, iron, manganese, and nickel. Findings included:

  • Some water sample results exceeded B.C. water quality guidelines at the B.C. sample sites. However, there were no exceedances of Alaska water quality standards for all samples taken downstream of the B.C.-Alaska border.
  • In some cases, element concentrations in water samples were above provincial guidelines upstream from mine sites, likely reflecting waters with naturally elevated mineral levels.
  • Sediment samples in both jurisdictions identified sites with concentrations of some elements above guidelines. Again, the elevated levels are largely attributed to naturally occurring mineral deposits in several areas.
  • Water quality testing showed significant agreement between data collected by government and data collected by industry.

Biological sampling looked at the presence of contaminants in migratory and resident fish species in the watersheds.

  • Fish sample results showed that the concentrations of elements in juvenile resident fish varied between sample sites in each watershed.
  • Resident fish species (such as Dolly Varden char) sample results in the Taku watershed revealed similar results both upstream and downstream of the Tulsequah Chief Mine.
  • In all fish sampled, the total mercury concentrations were below Health Canada’s maximum limit for human consumption.