Trace Element Concentrations in Mountain Forest Soils of Maine.

Human activity, sometimes stretching back centuries, has caused short- and long-range transport of trace elements. Trace elements and other pollutants are found in high elevation forest ecosystems via inputs from parent material, deposition, interception of wet cloud moisture, and bioaccumulation/cycling from the vegetation. The purpose of this research was to assess spatial and temporal changes in trace element concentrations on mountains in Maine. Surface mineral horizons, organic horizons, and leaf samples were collected from different elevations on six Maine mountains. Samples were digested and analyzed using ICP emission spectroscopy for As, Cd, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn. Organic soil trace element concentrations were spatially variable, always higher than those in the mineral fraction, tended to be higher than those reported in the past, and tended to increase with elevation. Some trace elements correlated very strongly with each other, namely Mn, Zn, and Cu, and correlations were stronger and more numerous in the organic than in the mineral horizons. Trace element concentrations were low in vegetation samples. Balsam fir trace element concentrations generally decreased with elevation, and were lower than in hardwoods.