Monitoring legacy arsenic in the Yellowknife area

Water Monitoring

The NWT Cumulative Impact Monitoring Program (NWT CIMP) funded a multidisciplinary research project with Carleton University that examined the recovery in Yellowknife area lakes from 50 years of arsenic pollution.  The project identified factors preventing recovery and biological consequences.

Key project findings:

  • Shallow lakes may have slower recovery rates because of under-ice redistribution of arsenic from sediments to overlying water.
  • Changes in winter flow due to climate change may affect the cycling of arsenic between sediments and overlying water under ice.
  •  Conditions under which there is increased oxygen under ice which can reduce the amount of arsenic being released from sediment.
  • Short-term experiments showed that arsenic in surface water reacts with sunlight to create a less toxic form of arsenic.

For additional information, see: