NWT RESEARCH DATABASE

Tags: physical sciences, water quality, environmental monitoring, fish, sediment quality, benthic invertebrates

Objective(s): To evaluate if there are differences in biological parameters among study sites and between years; and to determine whether observed differences from the most recent Environmental Effects Monitoring study are still present.

Project Description: The objectives are to evaluate if there are differences in biological parameters among study sites and between years of the Environmental Effects Monitoring study are still present and whether any differences are the result of current mining practices, historical mining practices, or a combination of the two. The design will include studies on fish (non-lethal sampling of slimy sculpin), benthic invertebrates (aquatic insects), water quality, and sediment quality within the same five study sites as were used in the 2012 Environmental Effects Monitoring study. The following is a list of methods specific to each parameter that will be sampled: Fish: Slimy sculpin will be captured using minnow traps and a backpack electrofisher. Minnow traps are baited cage style traps that capture and hold small fish. Twelve traps will be set at each site for 24 hours, then fish will be examined, measured and returned to the river alive. Electrofishing uses electrical current to attract and stun fish. All captured fish will be held in a live-well until sampling is complete then fish will be examined, measured and returned to the river alive. Both methods are designed to be non-lethal, however if any individual fish die during sampling, additional structures will be taken from them to provide aging data. Benthic Invertebrates (Aquatic Insects): Invertebrates will be collected using a Hess Sampler, which is a circular tube that covers a fixed area, with mesh netting on the side wall to allow water to flow through it, and has a mesh net that funnels insects into a container where they are captured. The sampler will be inserted into the substrate (stream bed) and the substrate will be hand scrubbed for 5 minutes. All invertebrates captured will be transferred to sample containers and preserved with ethanol (alcohol), until they are shipped to a laboratory for counting and species identification. Water Quality: Water will be collected at each site using laboratory supplied bottles. Samples will be filtered if needed using a hand-held pump filter, and then preserved with chemicals if necessary. Samples will be refrigerated until they are shipped to the laboratory in coolers for analysis. The samples will be analyzed for metals and other standard parameters as required by the Metal Mining Effluent Regulations. The results will be compared against the Canadian Council of Ministers of the Environment guidelines for the protection of aquatic life. Sediment: Sediment samples will be taken at each site at the same time as the invertebrates. Sediment will be collected using an Ekman Dredge which is a metal spring loaded sampler that "grabs" a set amount of sediment from the stream bed. Sediment that is not in direct contact with the sampler (to avoid influencing metals analysis) will be transferred to a sample container. The containers will be refrigerated until they are shipped to the laboratory in coolers for analysis. The samples will be analyzed for metals and other standard parameters as required by the Metal Mining Effluent Regulations. The results will be compared against the Canadian Council of Ministers of the Environment Interim Sediment Quality guidelines. A report summarizing the results and analysis of the data collected will be prepared as required by the Metal Mining Effluent Regulations. The report will be submitted to the North American Tungsten Corporation Ltd. and to the appropriate government agencies. The fieldwork for this study will be conducted from August 15, 2015 to September 25, 2015.