Elemental Analysis of Boundary Waters Canoe Area lichens of the Superior National Forest: Final report

Abstract

In the final report on the lichens and air quality in the Boundary Waters Canoe Area (Wetmore, 1987) it was recommended that a restudy of the elemental analysis of lichens be done every five years. This report is on the first restudy done in 1992. In this study four species of lichens were collected during June, 1992 at the same localities as the previous study. The methods used were the same as in the previous study. The results of this study showed some increase in five elements (AI, Fe, Cu, Cr and K) in lichens. These elements may come from airborne dust or their increase may be due to random changes. ANOVA and pairwise comparisons by statistical analysis showed a significant increase in the element group {AI, Fe, Cr, S} in all species at most localities but a decrease in {B} at all localities. The Trap Lake locality was more freqently at the low end of the accumulation scale and Lac La Croix was more frequently at the high end. It is concluded that there probably has been no important change in the air quality in the wilderness. The recommendation is made that the periodic five-year restudy of elemental analysis be continued.