The LNAPLs (Light Non-Aqueous Phase Liquids) documents help users set appropriate LNAPL remedial objectives in the context of a site-specific LNAPL conceptual site model, provide tools to screen 17 LNAPL remedial technologies to identify an optimal LNAPL remedial technology to achieve the objectives, and provide example performance metrics that would be set to gauge remedial effectiveness and demonstrate achievement of the objectives. Natural source zone depletion (NSZD) for LNAPLs is also summarized, including the processes involved, their rates, and potential for long-term progress.
The Biofuels document addresses the causes and prevention of post-manufacture biofuel releases, impacts to environmental media, characterization methods, remedial responses, and stakeholder concerns.
The Mass Flux document summarizes the concepts underlying mass flux and discharge, their potential applications, and case studies of the uses of these metrics.
Petroleum vapor intrusion (PVI) is a subset of vapor intrusion (VI) and is the process by which volatile petroleum hydrocarbons (PHCs) released as vapors from light nonaqueous phase liquids (LNAPL), petroleum-contaminated soils, or petroleum-contaminated groundwater migrate through the vadose zone and into overlying buildings. Fortunately, in the case of PHC vapors, this migration is often limited by microorganisms that are normally present in soil. The organisms consume these chemicals, reducing them to nontoxic end products through the process of biodegradation. The extent and rate to which this natural biodegradation process occurs is strongly influenced by the concentration of the vapor source, the distance the vapors must travel through soil from the source to potential receptors, and the presence of oxygen (O2) in the subsurface environment between the source and potential receptors.