Tuesday, April 1, 2008 : 11:00 a.m.

Plume Stability Analysis: An Innovative Method for Assessing Contaminant Plume Stability

Joseph A. Ricker, PE and Brian C. Laine, EIT, PG, Premier Environmental Services

When characterizing groundwater contaminant plumes, there are numerous methods for evaluating laboratory data. Typically, the data are tabulated and groundwater concentrations are presented on a site figure. Often contaminant concentration isopleth maps are developed to evaluate temporal changes in the plume boundaries.  In many cases this is the extent of the evaluation.  However, it is becoming more important to understand and effectively communicate the nature of the plume in terms of its stability (i.e., is the plume growing, shrinking, or stable?).  Evaluating plume stability is important for most remediation sites; however, it is of primary importance when evaluating natural attenuation sites.  USEPA (1998) states the primary line of evidence in evaluating natural attenuation is historical ground water chemistry data that demonstrate a clear and meaningful trend of decreasing contaminant mass and/or concentration over time.

Plume Stability Analysis (PSA) is a method for evaluating plume stability using innovative techniques to calculate and assess historical trends in various plume characteristics including area, average concentration, contaminant mass, and center of mass.  Contaminant distribution isopleths are developed for several sampling events and the characteristics mentioned above are calculated for each event using numerical methods and engineering principles. A statistical trend analysis is then performed on the calculated values to assess temporal trends and ultimately demonstrate plume stability. This presentation will also demonstrate the importance of using grid files generated from contouring and spreadsheet software eliminating both spatial and temporal human bias. 

PSA has been used at wood treating and chemical manufacturing sites to effectively demonstrate the stability of contaminant plumes, including carbon tetrachloride, pentachlorophenol (PCP), creosote, naphthalene, benzene and chlordane, among others. Although other methods for assessing contaminant plumes exist, PSA has been shown to be cost effective, efficient, reliable and applicable to any site with historical analytical data and a base map.

Joseph A. Ricker, PE, Premier Environmental Services Mr. Ricker is a registered professional engineer who provides technical expertise in Premier’s Memphis office. He has developed ambient air monitoring programs, site investigation work plans, long-term monitoring and maintenance programs, groundwater monitoring programs, and air dispersion analysis models. Mr. Ricker has provided technical support for natural attenuation projects and managed operations and maintenance for groundwater treatment plants. Mr. Ricker has a M.S. in Civil Engineering from the University of Memphis and a B.S. in Civil Engineering from Rose-Hulman Institute of Technology.

Brian C. Laine, EIT, PG, Premier Environmental Services Mr. Laine is a registered professional geologist and engineering intern. He is experienced in: groundwater modeling; contaminant transport; contaminant plume stability; innovative and standard remedial design and implementation; design and construction of landfill caps; and hazardous waste classification. Mr. Laine is also experienced in environmental activities pertaining to retail petroleum sites as well as the development of health and safety plans for environmental sites and implementation of client protocols. Mr. Laine has a B.S. and an M.S. in Geological Engineering from the University of Mississippi.


2008 Ground Water Summit