Improved Field Evaluation of NAPL Dissolution and Source Longevity
Abstract
DoD needs improved methods for estimating the mass of NAPLs in subsurface environments contaminated from past releases of these compounds. In addition, predicting their persistence into the future and the impact of NAPL source reduction on the time to achieve RAOs at compliance locations remains a significant challenge at these sites. Data are required to support scientifically defensible decisions regarding when and to what intensity active remediation efforts should be pursued at NAPL-contaminated sites before transition to passive remedies such as natural attenuation. The primary objective of this project was to evaluate a methodology to improve decision making on the extent of source remediation required to meet RAOs at both LNAPL and DNAPL impacted sites. Current techniques to estimate the persistence of NAPL sources are very uncertain without better specification of the mass of NAPL, the constituents of the NAPL, the NAPL architecture (i.e., the geometry of the NAPL distribution in the subsurface), and the dissolution rate of NAPL components in groundwater (referred to collectively in this report as the SZD function). The traditional approach to characterizing the SZD function involves estimation of NAPL dissolution rates from concentration measurements in discrete locations in the downgradient plume multiplied by an estimated groundwater velocity calculated from site-specific data.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 2011
- Accession Number
- ADA579185
Entities
Organizations
- Environmental Security Technology Certification Program