A 2001 study of Cleveland, Ohio brownfield surface soil contamination led to the examination of state regulatory guidance values for soils. Surface soils were of particular interest since these generally pose the greatest risk to human health at brownfield sites. This investigation initially focused on heavy metals, common contaminants at Cleveland brownfields. However, the observation of significant variability in guidance values applied to Cd, Cr, Cu, Pb, Ni, and Zn led to questions about other state-regulated components and ultimately to research examining the origins, magnitudes, and explanations for regulatory guidance value variability.

The results presented here are based on the compilation of an 18,776 state surface soil database assembled from regulatory guidance for organic, inorganic, and element contaminants. All values were captured electronically from internet sources. The structure of each guidance value dataset was then standardized in a database-compatible format. Chemical Abstract Service (CAS) registry numbers were added to each record if they were not already provided. Identification of all records by CAS number resolves the problem of chemical synonyms. All value datasets were then assembled into the ACCESS database S3GVD (State Surface Soil Guidance Value Database)

Statistical analysis is presented to characterize the nature and extent of variability in state surface soil guidance values. The organics, inorganics, and elements most and least commonly regulated and the range of guidance values are discussed. Log-scale Ordered Column Diagrams (LOCDs) are used to explore the nature of individual chemical guidance value distributions.