WHATS IN MY DIRT? – USE OF THE NATIONAL GEOCHEMICAL SURVEY TO DETERMINE ECOREGIONAL BACKGROUND VALUES FOR ELEMENTAL CONSTITUENTS IN ARKANSAS: A PROCESS, DEMONSTRATION, AND EXAMPLE APPLICATION

Federal land managers face a variety of challenges while managing the environmental impacts of various land uses. Informed decision-making requires empirically based, locally relevant resource information set in the context of natural background conditions and federal regulatory limitations. Environmental geochemicals, including major, minor, and trace elements, occur naturally with varying concentrations, but these values can be altered by a variety of factors which include land uses. Baseline values and the variability of such concentrations are important reference points for including in monitoring and environmental analysis activities.

This study investigates the environmental concentrations of a select group of elemental chemical constituents across the ecoregion classifications in the state of Arkansas. The data for this study originates from the National Geochemical Survey (NGS) conducted by the U.S. Geological Survey (USGS, 2004). This investigation will demonstrate the utility of the NGS for determining empirically based locally relevant information for use in land management applications. A process for obtaining relevant background values of environmental constituents is detailed. The outcome of such an assessment can be incorporated into monitoring activities, management plans, environmental analysis, and restoration activities.

An example application, using the outcome from this process, is showcased by the construction of a decision support system which incorporates background values to evaluate elemental constituents derived from the chemical analysis of sediment samples.