Trace metal geochemistry in spodosols of the northeastern United States

Long-term or postglacial (~~12 000-year) net fluxes of Pb, Cu, Zn, Ni, Cr, and Co through three Spodosols, formed from different parent materials, were calculated using mass-balance modeling. Metal contentsin vegetation and O horizons were also estimated and measured, respectively. Total metal contents in mineral horizons were fractionated into different operationally defined pedogenic phases using a sequential extraction technique. With few exceptions, the three soils had significant leaching losses for all trace metals (from 7--508 kg ha{sup}- 1{end}), the greatest losses generally occurring in the E and upperB horizons. The magnitude of losses by leaching varied with parent material, as a result of differences in weatherabilities of mineral suites. Combined metal contents in vegetation and O horizons, which mayoriginate from anthropogenic additions as well as mineral weathering, are significantly large in some cases; however, these metal amountsare apparently not large enough to offset long-term leaching losses from the underlying mineral soil profiles. Some B and C horizons had net accumulations of extractable Pb, Cu, and/or Ni-bearing phases. Based on the sequential extraction procedure used, the extractable metal forms are probably pedogenic Fe oxide- and/or organic-bound phases.One soil apparently gained Cu (~~38 kg ha{sup}-1{end}), which may have been from atmospheric deposition. [ABSTRACT FROM AUTHOR]