Baseline concentrations of 15 trace elements in Florida surface soils

The objective of this study was to establish baseline concentrations for 15 potentially toxic elements (Ag, As, Ba, Be, Cd, Cr, Co, Hg, Mn, Mo, Ni, Pb, Sb, Se, and Zn) based on 448 representative Florida surface soils using microwave assisted HNO3-HCl-HF digestion. Baseline concentrations of those elements were (mg kg(-1)): Ag 0.07-2.50, As 0.02-7.01, Ba 1.67-112, Be 0.04-4.15, Cd 0-0.33, Cr 0.89-80.7, Cu 0.22-21.9, Hg 0.00075-0.0396, Mo 0.13-6.76, Ni 1.70-48.5, Pb 0.69-42.0, Sb 0.06-0.79, Se 0.01-1.11, and Zn 0.89-29.6, respectively. Upper baseline values for most elements corresponded with these reported in literature, except Ba, Hg, Mn, Sb, and Zn, which were 3 to 23 times lower. Soil properties, including pH, organic carbon (OC), particle size, cation exchange capacity (CEC), available water, extractable base, extractable acidity, total Ca, Mg, P, K, Fe, and At concentrations, were related to metal concentrations using factorial analysis. Eight factors were identified (total Fe and Al, CEC, pH, clay, OC, total Ni and Mo, total Sb and Pb, and total Hg) and accounted for 87% of the total variance, suggesting that metal concentrations were primarily controlled by soil compositions. Multiple regression of elemental concentrations against total Fe, total Al, clay, OC, CEC, and pH was significant for all elements. Partial correlation coefficients indicated that total Fe and/or Al explained most of the variance for Mn, Ni, Ba, Be, Hg, As, Cd, Cr, Cu, Mo, Pb, and Zn concentrations. Most of the variance in Se was related to clay, whereas those of Ag and Sb related to clay and total Al.