API Interactive LNAPL Guide — Version 2.0.4 A comprehensive and easy - to - use electron ic information syst em and screening utility. The guide is designed to provide an overall approach for evaluating light nonaqueous phase liquid (LNAPL) at a site, assessing its potential risk, quantitatively defining mobility and recoverability, developing remedial strategies, and examining methods to enhance site closure opportunities. The guide includes the following:• 11 primers covering all aspects of LNAPL from LNAPL basics to remediation; • 14 assessment tools, including API - LNAST Version 2.0, “Charbeneau” spreadsheets for LNAPL recovery (August 2003), the API LNAPL Parameter Database; • LNAPL decision - making frameworks;• videos and animat ed figures; and • an extensive reference list. February 2006 | Available for download at http://www.api.org/oil - and - natural - gas/environment/clean - water/ ground - water/lnapl/interactive - guide Publ 4761 Technical Protocol for Evaluating the Natural Attenuation of MtBE Addresses data collection, evaluation, and interp retation procedures that consider the physical, chemic al, and biological properti es of methyl tert - butyl ether (MtBE) and other oxygenates and degradation byproducts. A tiered approach is provided that can be used by stakeholders to interpret several lines of evidence to evaluate natural attenuation on a site - specific basis. Several resources are provided to su pport an MNA evaluation, including the following: • a review of basic scientific principl es relevant to the evaluation of MtBE natural attenuation, including bi odegradation and physicochemical attenuation mechanisms; • a discussion of data that can be used to assess MtBE (and other oxygenates or degradation by products) natural attenuation; • technical references for relevant chem ical properties, analytical methods, and field sampling techniques; • guidance for data quality assur ance and interpretation, including statistical analysis; and • guidance