Author(s): Lena Q Ma
Concentrations and distributions of 11 elements—Hg, Cd, As, Cu, Cr, Pb, Ni, Zn, Mn, Al, and Fe—in 40 Florida soil profiles (94 soil samples) were investigated. The soils were classified as Spodosols, Entisols, and Ultisols, representing major mineral soils in Florida. The geometric mean concentrations of Hg, Cd, As, Cu, Cr, Pb, Ni, Zn, Mn, Al, and Fe in surface soils (A horizons) were 0.0042, 0.21, 1.1, 3.7, 3.9, 4.1, 6.5, 12, 25, 730, and 820 mg kg−1, respectively. Metal concentrations in these soils were lower than those of published values of Florida agricultural soils and U.S. soils. Metal contents, excluding Cd and Mn, were strongly correlated with clay content (r = 0.35–0.77), and some metals (Cr, Ni, Pb, and Al) were correlated with cation exchange capacity (r = 0.23–0.35). Metal distributions in soils, therefore, reflected parent-material and pedogenic factors determining clay content variations between and within soil profiles. Generally, metal contents in soils decreased in the order of Ultisols > Entisols ≥ Spodosols and Bt > Bh > A ≥ E horizons. All metals except Cd, Hg, and Mn were concentrated in Bt horizons; As, Cu, Cr, Fe, and Al were enriched in Bh horizons, where clay and organic matter had accumulated.