"The volatilization of hazardous organics from hazardous waste land treatment systems was evaluated in laboratory and field studies using complex petroleum refining hazardous wastes. Laboratory experiments were conducted using two soils and an inert construction sand to investigate the emission flux rates of seven volatile constituents, i.e., benzene, toluene, ethylbenzene, p-, m-, o-xylene, and naphthalene, from API Separatory Sludge and Slop Oil Emulsion Solids wastes in column and flask laboratory units. Emission flux rates were monitored as a function of waste application rate, application method (surface versus subsurface), soil type and soil physical characteristics. Field experiments were conducted at an active petroleum refinery hazardous waste land treatment site to which a combined API Separator Sludge/DAF bottom sludge was surface applied. Pure constituent collection and quantification in both laboratory and field studies were carried out using an emission flux chamber and split stream Tenax sorbent tube concentration system. Suggested operating procedures in terms of purge flow rates, split stream sampling rates, sample collection volumes for minimal contaminant sorbent tube breakthrough, etc., are presented. Measured laboratory and field data were compared to the Thibodeaux-Hwang Air Emission Release Rate (AERR) model in an effort to validate this state-of-the-art land treatment emission model. Once specific data are collected which describe the physical environment of the land treatment system, prediction of pure constituent air emissions from surface application and tilling can be provided by the model, within a factor of two to ten, even for complex hazardous wastes applied to complex soil systems."