Nasser, N.A., Patterson, R.T., Roe, H.M., Galloway, J.M., Falck, H., Palmer, M.J., Spence, C., Sanei, H., Macumber, A.L., Neville, L.A. 2015. Lacustrine arcellina (testate amoebae) as bioindicators of arsenic contamination. Microbial ecology.
Arcellaceans (testate amoebae) were examined from 61 surface sediment samples collected from 59 lakes in the vicinity of former gold mines, notably the Giant Mine, near Yellowknife, Northwest Territories, Canada to determine their utility as sensitive bio-indicators of arsenic (As), a byproduct of gold extraction at mines in the area as well as occurring naturally from ore bearing outcrops. Cluster analysis (Q-R-mod) and detrended correspondence analysis (DCA) reveal five arcellacean assemblages that are related to varying As concentrations in the sediment samples. Redundancy analysis (RDA) showed that 14 statistically significant environmental parameters explained 57% of the variation in faunal distribution, while Partial RDA indicated that As had the greatest influence on assemblage variance (10.7%; p<0.10). Stress-indicating species (primarily centropyxids) characterized the faunas of samples with high As concentrations (median= 274.7 ppm, max > 10000 ppm, min=16.1 ppm, n=30), while difflugids-dominated assemblages were prevalent in substrates with relatively low As concentrations (median=30.8 ppm, max=905.2 ppm, min=6.3 ppm, n=23). Most of the lakes with very high As levels are located downwind (N and W) of the former Giant Mine roaster stack where refractory ore was roasted and substantial quantities of As were released (as As2O3) to the atmosphere in the first decade of mining. This spatial pattern suggests that a significant proportion of the observed As, in at least these lakes, are industrially derived. The results of this study highlight the sensitivity of arcellaceans to As and confirm that the group has considerable potential for assessing the impact of As contamination on lakes.
pdf coming soon