Natural attenuation is an important mechanism at many contaminated sites because it can limit pollutant migration and simultaneously reduce contaminant mass in the subsurface. Characterizing these mechanisms involves both qualifying and quantifying the impact of natural attenuation by establishing a comprehensive field sampling, analysis, and data interpretation program which specifically meets well defined data quality objectives. Finally, the application of natural attenuation to the selection of a preferred remedial alternative can be accomplished once the baseline data is collected, analyzed, and interpreted.

Three lines of evidence are used to document and determine the specific natural attenuation processes that may be occurring at a given site. These lines of evidence are:

• Reduction in parent compound concentrations downgradient of the source;
• Appearance of products of degradation including appearance of daughter products, depletion of electron acceptors and donors along the flow path, and increasing concentrations of metabolic byproducts along the downgradient path; and
• Direct microbiological evidence of microflora capable of degrading the constituents of concern under the conditions observed.

TEA maintains an in-house field laboratory that can be mobilized to the field to collect real-time biogeochemical data to document natural attenuation activities that may be occurring in subsurface environs.

TEA also has in-house microbiologists and close associations with fixed-base laboratories that specialize in custom microbiological and microcosm studies, and specialty analytical services to support in-situ remediation evaluations.

For more information, please contact Frank Manale at 225-767-3880 or fmanale@teainconline.com.