Quantitative Contaminant Plume Analysis for Assessment and Remediation
Douglas S. Kilmer1, P. G., Gary Mast1, and Stuart Rhodes2
1Horizon Environmental Corporation, Grand Rapids, MI 49512 [email protected], [email protected]
2Rio Tinto Services Ltd., Sydney, Australia, [email protected]
Traditionally, contaminant plume evaluations have used qualitative graphical assessments based on an individual’s interpretation of contaminant extent and concentration trends from spatially and temporally discrete data (i.e., monitoring well data). Decisions based on these types of evaluations contain an inherent degree of arbitrariness introduced by the evaluator(s) (i.e., human bias). We present examples of the application of a quantitative geospatial and statistical method suggested by others. The method determines a plume’s average concentration and distribution, providing an improved basis for environmental response decision making.
The presented method applies a plume-wide geospatial analysis technique, managing all data sets in a consistent manner. The method is simple, relatively rapid, and employs common desktop spreadsheet and contouring software to calculate average contaminant concentrations, contaminant mass, and lateral plume extent relative to an identified criterion (e.g., regulatory standard). Examination of the plume’s behavior as a whole, rather than on a monitoring point by monitoring point basis, provides an improved understanding of temporal changes in the plume’s internal conditions.
This method provides an improved means by which regulatory concurrence with demonstrations of remediation (e.g., monitored natural attenuation or hydraulic containment) can be obtained. Beyond previous suggestions, we also posit this method can be employed in a greater range of applications as an effective tool to make decisions concerning both site assessment and remediation. The impacts of individual datasets also become apparent relative to the overall temporal character of the plume. Examples of this method applied to both aromatic and chlorinated hydrocarbon releases are presented.
AAPG Search and Discovery Article #90095©2009 AAPG Eastern Section Meeting, Evansville, Indiana, September 20-22, 2009