NWT RESEARCH DATABASE

Regions: Dehcho Region

Tags: contaminants, mining impacts, ecological indicators, hydrology, metals, benthic invertebrates, ecological monitoring, remediation

Objective(s): The objectives of this research are two-fold: 1) Identify an ecological indicator that can monitor changes in loadings of metals in the South Nahanni Watershed. This work is scheduled for completion in 2007-2008. 2) Establish a monitoring program that can quantify the cumulative effects of mining activities on the health of streams in the South Nahanni Watershed. This work is scheduled for completion in 2008-2009 (field collections) to 2009-2010 (processing of samples, and data interpretation and report production).

Project Description: The objectives of this research are two-fold: 1) Identify an ecological indicator that can monitor changes in loadings of metals in the South Nahanni Watershed. This work is scheduled for completion in 2007-2008. 2) Establish a monitoring program that can quantify the cumulative effects of mining activities on the health of streams in the South Nahanni Watershed. This work is scheduled for completion in 2008-2009 (field collections) to 2009-2010 (processing of samples, and data interpretation and report production). Study component 1 - Identifying an ecological indicator of trace metals loadings in streams in the South Nahanni Watershed. Introduction: Monitoring of metal loadings in Nahanni National Park Reserve could be accomplished using one of several physical or biological endpoints. The researchers will complete an intensive set of field studies in 2007 that will identify which endpoint can be used to monitor metal loadings. Previous research has shown that sampling of select sculpin tissues (e.g., livers, muscle tissues) and water to document loadings of metals in the South Nahanni Watershed is problematic because of low densities of slimy sculpin and high natural variation in concentrations of metals in water. Sampling: the researchers will design and implement a field program to quantify spatial variation in concentrations of metals in water, sediment, benthic algae and macroinvertebrates, and fish at sites upstream and downstream of the Cantung and Prairie Creek mines. Samples of water, sediment, algae, macroinvertebrates and fish will likely be collected from a total of 8 sites, located at each of the 2 mines. One site will be located immediately adjacent to each mine with an additional 3 sites, at each mine, located upstream of the mine (i.e., 0.5, 1 and 2 km upstream of the mine) and an additional four sites located downstream (0.5, 1, 2, and 4 km downstream) of the mine. Sites will be sampled once in the fall of 2007. The researchers will complete more intensive sampling at 2 of these sites to evaluate the effects of algal biomass on metal loadings in algal communities. Taken together, these data will quantify concentrations of metals in water and specific parts of the food web, and can also be used to determine whether levels of metals in one component of the food web can be extrapolated to other parts of the food web. Study component 2 - Developing monitoring tools to quantify the health of ecological integrity of streams in the South Nahanni Watershed. Introduction: Benthic macroinvertebrates that live on, or within the stream bottom, are widely used to measure the ecological health of streams, and are routinely used to detect impairment resulting from many types of human activities. Evaluations of ecological health of stream using invertebrates can be completed using a number of different sampling designs and statistical analyses. Sampling: the researchers will design and implement a field program to quantify spatial variation in benthic invertebrate communities at approximately 80 sites (i.e., short reaches of streams) in the South Nahanni Watershed. Sites will be located on both small streams and rivers. Select water chemistry and habitat features at study sites will also be measured. Sites will be sampled once in the fall of 2008 with data interpretation and report production scheduled for completion in 2009-2010. The researchers anticipate combining data from these efforts with two existing databases held by Parks Canada Agency (Mr. Doug Tate, Nahanni National Park Reserve) and Dr. Monique Dubé (University of Saskatchewan). When data from the field program are augmented with existing databases they will be used to assess the effects of mining activities on the health of streams in the entire South Nahanni Watershed, including that which encompasses the Nahanni National Park Reserve. At the completion of year 1 the field results will be compiled. Results will be presented to the project’s partners at a progress meeting scheduled tentatively for May 2008. The meeting will likely be held in either Fort Simpson, Yellowknife or another location deemed to be most suitable to meeting participants. Similar efforts will be taken to ensure that results from Component 2, scheduled for completion in 2009-2010 can also be communicated to northern communities. A scientific publication will be prepared and submitted to the partners for comment. These results will also be communicated to Parks Canada staff at a national scientific meeting. Results will also be communicated to personnel at Cantung and Prairie Creek mines for their consideration. The researchers will also provide their study findings to the Mackenzie Valley Land and Water Board for their consideration. In addition, a layman’s summary of the research will be compiled and provided to northern communities. Results of this research will be used to make recommendations to customize northern monitoring programs and are directly relevant to both mines in the South Nahanni Watershed and to Parks Canada Agency as they develop ecological monitoring programs. When combined with recent research completed by Dr. Monique Dubé (University of Saskatchewan), study results will support the development of dose response curves for key northern contaminants to assist with development of permit discharge limits. Fieldwork will be conducted from September 06 to 30, 2007 at 8 sites immediately adjacent to each of the two mines located within the South Nahanni Watershed. The first is the Cantung mine (North American Tungsten, 61 58'06.5 N, 128 13'28.7 W) that operates in the northwest portion of the South Nahanni Watershed and releases water from the mine to the Flat River. The second mine is the Prairie Creek Exploration Camp (Canadian Zinc, 61 33'05.5 N, 124 47'32.833 W) located in the southeast portion of the South Nahanni Watershed.