Vertical distribution of major, minor, and rare elements in a Haplic Podzol
Total and 0.2 M HCl-soluble concentrations of 44 mineral elements were studied in four profiles (0-110 cm) of a Haplic Podzol, developed from a 13,000-14,000-year-old quartzite-gneiss moraine deposit in south Sweden. Depending on element and soil fraction of the element considered, concentration maxima occurred in different horizons in the soil. The E horizon was impoverished in HCl-soluble fractions of nearly all and of total contents of most elements. Most alkali (sodium, potassium, rubidium, and caesium), alkaline-earth (magnesium, calcium, strontium, and barium), and several divalent transition metals (vanadium, cobalt, nickel, zinc, cadmium, mercury, and lead) had their HCl-soluble concentration peaks in the topsoil (01 or 02 horizons, rich in organic matter), iron and gallium in the B1 horizon, aluminium together with chromium, lithium, beryllium, scandium, silicon, thorium, zirconium, and molybdenum in the B2 horizon. HCl-soluble lanthanum, yttrium, and the lanthanides (cerium, dysprosium, gadolinium, neodymium, praseodymium, samarium, thulium, and ytterbium) peaked further down in the soil. Factor (PCA) analysis (all samples and horizons considered in the HCl extraction) arranged the elements in three groups. One group was composed of the rare-earth elements but also included several less heavy transition metals as well as phosphorus, boron, and aluminium. A second group, also containing organic carbon, comprised most alkali and alkaline-earth elements but also heavy metals such as nickel, copper, lead, zinc, cadmium, and mercury. Iron and gallium were discerned as a third group in the PCA analysis. Relative budget estimates based on total amounts per unit soil volume indicated that the greatest losses since deglaciation from the E+B horizons had occurred of alkaline-earths, lanthanides, uranium, and some divalent transition metals (cadmium, cobalt, and zinc). Accumulation in the 01 and 02 horizons, however, had compensated for the losses from the mineral soil of particularly cadmium and lead, to a large extent elements originating from atmospheric deposition of long-distance transported pollutants.
- Biology and Life Sciences
- trace element
- weathering loss
- ISSN: 0016-7061