Major and Trace Elements of Selected Pedons in the USA

Abstract

Few studies of soil geochemistry over large geographic areas exist, especially studies encompassing data from major pedogenic horizons that evaluate both native concentrations of elements and anthropogenically contaminated soils. In this study, pedons (n = 486) were analyzed for trace (Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn) and major (Al, Ca, Fe, K, Mg, Na, P, Si, Ti, Zr) elements, as well as other soil properties. The objectives were to (i) determine the concentration range of selected elements in a variety of U.S. soils with and without known anthropogenic additions, (ii) illustrate the association of elemental source and content by assessing trace elemental content for several selected pedons, and (iii) evaluate relationships among and between elements and other soil properties. Trace element concentrations in the non-anthropogenic dataset (NAD) were in the order Mn > (Zn, Cr, Ni, Cu) > (Pb, Co) > (Cd, Hg), with greatest mean total concentrations for the Andisol order. Geometric means by horizon indicate that trace elements are concentrated in surface and/or B horizons over C horizons. Median values for trace elements are significantly higher in surface horizons of the anthropogenic dataset (AD) over the NAD. Total Al, Fe, cation exchange capacity (CEC), organic C, pH, and clay exhibit significant correlations (0.56, 0.74, 0.50, 0.31, 0.16, and 0.30, respectively) with total trace element concentrations of all horizons of the NAD. Manganese shows the best inter-element correlation (0.33) with these associated total concentrations. Total Fe has one of the strongest relationships, explaining 55 and 30% of the variation in total trace element concentrations for all horizons in the NAD and AD, respectively.

Heavy metal sources and associated risk in response to agricultural intensification in the estuarine sediments of Chaohu Lake Valley, East China

“…When compared with the previous two pathways, agricultural activities are known to be significant non-point sources of heavy metals in the environment [9,10]. Different methods, such as EF and CA, have been widely applied in investigations to identify pollution sources and to apportion natural vs. anthropogenic contributions [11][12][13]. Sedimentation processes usually occur during the subsequent transport of heavy metals from these anthropogenic sources to the surface and ground water [14].…”

Geochemistry in the modern soil survey program

“…Municipal sludge, waste from smelting, poultry, and swine manure (Reed and Martens 1996) Seasonal changes in pH may influence metal solubility especially in wetlands (Gambrell 1994), where associated fluctuations in salinity also influence elemental sorption and mobility. Correlation of data routinely obtained during soil survey activities (e.g., Fe oxides, carbonates, salinity, particle size, organic matter) can be useful predictors of the concentration and reactivity of trace elements at the landscape scale (Burt et al 2003b;Ma et al 1997;Pardue et al 1992;Mermut et al 1996). This relationship provides evidence of the importance of common soil components influencing pedogenic distribution and supports the examination of geochemistry of soils within the context of a soil survey.…”

“…Quality assurance samples (blank, duplicate, and certified reference material) were included for every 28 samples in the digestion process. Evaluation of standard reference material is described in Burt et al (2003b).…”

“…Soil variability has been extensively studied, approached from both a theoretical, modeling basis (Heuvelink and Webster 2001;McBratney et al 2000) and by evaluation of variability for specific soil properties based on scale of mapping (Leenhardt et al 1994). Geochemical variability by soil order has been evaluated (Ma et al 1997;Chen et al 2002;Burt et al 2003b) and geochemical variability between different series has been documented in statewide studies. Yet, utility of background values established for representative pedons should examine variability among pedons of a single series as well.…”

“…These analyses were necessitated by the increasing demand for these data by soil survey clientele and soil scientists of the NCSS requiring information on native (background) concentrations of trace elements in soils (Wilson et al 2002;Burt et al 2003b). Soil survey is in a unique position to provide data on the complete spectrum of elemental distribution in soils as defined by extractable, exchangeable, soluble, and total forms, accompanied by associated laboratory characterization of physical, chemical and mineralogical properties, and site specific field data.…”