| The purpose of this research is to evaluate the quality of lake bottom sediment as an environmental indicator, and assess its contribution to environmental planning and management in the Coppermine River basin. Using a mixed-method approach, the research incorporates both scientific and management perspectives of environmental indicators.; The results of the interviews with interested parties help to describe the context for general indicator development and evaluation in the Coppermine River basin. The majority of participants believe that environmental management should be designed to maintain current aquatic ecosystem health. Representatives from every group described a vision of the basin where the state of health would be unaltered.; The sediment core collection and analyses reveal the spatial and temporal variability of bottom sediment in four lakes. Sedimentation rates are low and comparable to other northern lakes, ranging from 101 g/m2/yr at Desteffany Lake to 156 g/m2/yr at Daring Lake. Several metal concentrations are significantly greater at Lac de Gras than at the other lakes, including arsenic, cadmium, copper, iron, manganese, nickel and zinc. The analyses highlight two main sediment quality issues. First, elevated metal concentrations are present in lake bottom sediment, which may cause adverse effects in aquatic biota and pose a risk to water quality. For example, arsenic, iron and manganese concentrations exceed sediment quality guidelines for the protection of aquatic life in the surface of the Lac de Gras core. Second, metal enrichment from anthropogenic activities, specifically LRTAP, is occurring in the headwaters region. For example, enrichment of mercury at Desteffany and Daring Lake, and possibly Lac de Gras, and enrichment of lead at Daring Lake and possibly Lac de Gras are the result of long-range atmospheric transport.; Using an indicator development framework developed from the literature, the results of the interviews and sediment analyses are combined to evaluate the quality of lake bottom sediment as an environmental indicator. The research concludes that lake bottom sediment, specifically metal and nutrient content, represents a good indicator of state for the basin. The indicator's greatest strengths are that it is able to document historic trends over time and is effective in indicating LRTAP, an important societal concern. The indicator's greatest weakness is its low sensitivity to change and coarse temporal resolution due to low sedimentation rates.; The research concludes that the indicator makes a significant contribution to environmental planning and management. First, the indicator can be used to report information, particularly information about historic trends. Second, the indicator can be used to facilitate communication between decision-makers and the public, provided the information is presented in an understandable language and format. Third, the indicator can be used to develop and evaluate policies, including policies related to the anthropogenic release of metals. (Abstract shortened by UMI.)... |
