influence of airborne road dust on the chemistry of Sphagnum mosses

(1) Chemical analysis of Sphagnum moss samples collected from a raised Sphagnum bog along a transect at right angles to and away from a gravel road at Pointe Escuminac, New Brunswick, Canada, shows that concentrations of the elements Al, Cr, Fe, La, Ni, Sc, Sm and V are strongly correlated with one another, and their concentrations decrease logarithmically away from the road to a distance of 200 m. These elements are deposited primarily in wind-borne soil dust. Concentrations of Na and Cl are correlated; their primary source is precipitation enriched by sea spray. Amounts of As, Cd, Pb, and Zn are also intercorrelated and vary independently of other elements; their primary source is air pollution. (2) Enrichment factors (EF)--(element concentration: Al concentration in sample divided by the same ratio in the earth's crust)--help to distinguish the primary sources of elements. Both the average enrichment factor and the degree of slope to the regression line of log(EF) vs. log[Al] indicate the degree to which the element is dependent on soil dust or some other factor as a primary source of atmospheric input to the bog, or is concentrated by the Sphagnum moss.