Formatted Title
Managing, Assessing, and Presenting Imperfect Chlorinated Solvent Data in Support of Environmental Litigation
Background/Objectives
Consultants are often called upon to support litigation cases for chlorinated solvent plumes. The data sets provided to consultants at the onset of a litigation project are often not the ideal data set where soil and/or groundwater samples are collected from within the required hydrostratigraphic units; the well screens do not straddle multiple units and the samples were not collected at the same time of year using the same sampling method. Usually, the consultant looks at the data and wishes things were done differently and wants to obtain more data using a consistent methodology. How does a consultant do this you ask? It’s by taking the information they do have and supplementing it with knowledge and understanding of how chlorinated solvent plumes migrate over time and space, available geological and hydrogeological mapping, and a lot of time spent honing imperfect data into a format that can be presented to the legal team and the client. At the end of the day sometimes you are lucky and are able to convince the legal team and the client that obtaining additional data would help support their case and you are able to do that and sometimes they decide to sit on the information and your recommendations for months or even years before circling back to you and asking you to dust off your work and proceed with the next phase of assessment.
Approach/Activities
This presentation will examine the data sets from at least three different litigation cases where the chlorinated solvent data that were provided were not perfect. Each case has a different level of data quality and quantity and is located within different geological and hydrogeological areas (shale bedrock, glaciofluvial deposits, and till) in Southern Ontario and would have one or more potential contaminant sources. The approaches used to manage and assess the data are comprised of the following:
- Extracting data from third party reports and organizing it so that the historical and current extent of the chlorinated solvent plume(s) is understood.
- Developing a conceptual site model (CSM) to understand the geological and hydrogeological conditions at each site.
- Investigating the historical use of the site and surrounding area to assess potential contaminant source locations.
- Examining the change in contaminant concentrations over time by using statistical analysis in addition to assessing the change in concentration of the initial contaminant(s) in relation to its (their) breakdown products.
- Assessing the spatial distribution of contaminations within different hydrostratigraphic units and over time.
Results/Lessons Learned
The results from taking poor data sets and transforming them into something that can be presented visually to a legal team and client and presented in a way that your findings can be understood by everyone will be provided (graphs, figures, etc. will be provided). Evaluation of the data sets will include supporting or refuting consultant findings and opinions and finding flaws within the data sets prior to presenting the information to a client. One of the key take aways will be that your initial understanding of the site/contaminant plume could be challenged and you may have thought “X” about you site, contaminant plume, etc. but after multiple rounds of groundwater monitoring and sampling, installation of additional monitoring wells across the site and within different hydrostratigraphic layers your understanding changes and the CSM changes and this new understanding needs to be presented to the legal team for evaluation and consideration in the next phase of the litigation.