ABSTRACT
This chapter discusses soil types, classification, and subsurface characteristics from the point of view of remedial choices and planning. Soils that are contaminated by petroleum products include the entire range of soil types from sands, glacial tills, and gravels, to sediments, silts, and clays. Contaminated soil types also include artificial fills, tailings and even abandoned landfills. Subsurface petroleum contamination is distributed in a complex mixture consisting of different physical states. Hydrocarbon contaminants move downward by force of gravity; some horizontal spreading will also occur because of capillary forces between the migrating liquid and soil particles. Migration of contaminants also depends on the type and porosity of the soil. Hydrocarbon flow velocities are proportional to viscosities, particle density, and soil conductivity. Soil descriptions are generally taken from well borings. Hollow stem augers are especially convenient for noting soil types and correlating with depth.
