Arcellaceans (testate lobose amoebae) were examined for 61 sediment surface samples from lakes in the vicinity of the Giant Mine near Yellowknife, Northwest Territories to; (1) quantify the impact of the mine on the Baker Creek Watershed region, (2) determine the utility of arcellaceans as indicators of arsenic and heavy metal contamination and gauge the success of remediation efforts. Several statistical methods, including cluster analysis, Deterended Correspondence Analysis (DCA), and Redundancy Analysis (RDA), were used to quantify the impact of mining activity on the arcellacean
assemblages. Cluster analysis revealed five arcellacean assemblages associated with a range of environmental conditions (e.g. polluted, transitional and remediated). Partial RDA results confirm that arsenic has the greatest influence on the arcellacean distribution, explaining 10.7% of the total variance. Stress-indicating species (e.g. Centropyxids) correlate with high arsenic concentrations, while species characteristic of more healthy lake conditions (e.g. Difflugids) dominate sites with significantly lower arsenic concentrations.