Although some state and federal agencies and other entities have guidance documents regarding soil background, there is not one comprehensive and widely accepted guidance document that summarizes the state of the science on this topic. This ITRC guidance document is intended to fill the gap by providing a comprehensive defensible framework for establishing and using soil background in risk assessments. It focuses on the process of establishing defensible background concentrations of naturally occurring or anthropogenic ambient chemicals to be used for risk assessment at contaminated sites.#Bioavailability of Contaminants in Soil#SoilBackgroundandRiskAssessment