Formatted Title
Automated Visual Tools for Source Distinction, Commingled Plume Differentiation, and Attenuation Assessment for Complex Chlorinated Compound Mixtures
Background/Objectives
Understanding chlorinated volatile organic compound (CVOC) compositional profile changes is crucial for developing accurate and useful conceptual site models. Furthermore, compositional profiles are a powerful tool for evaluating biological and monitored natural attenuation remedy success at sites with CVOC mixtures in one or more media. Changes in CVOC compositional profiles may reveal previously unknown sources, serve to differentiate between areas of impact related different sources, and provide lines of evidence for complete degradation of CVOC that (under some conditions) require multiple degradation steps (e.g., reductive dechlorination). Historically, evaluating CVOC compositional changes has required processing large data sets by repetitive manual methods. Making sense of constituent mixtures through space and time also requires standardized visual tools that are designed to enable rapid comparisons. PowerBI Report Builder is an effective tool to develop figure templates that include standardized charts generated by querying an EQuIS database. This approach allows for nearly instantaneous generation and viewing of compositional profiles and trends. In the past, generation of these materials by manual methods may have taken weeks to months. Case studies that illustrate the utility of these visual tools will be presented.
Approach/Activities
A PowerBI Paginated Report was developed that includes multiple customizable charts for any combination of data sets from a project’s EQuIS database. These charts are generated based on the user’s selection of monitoring locations, constituents, and date ranges of interest and result in instantaneously populated figure templates ready for deliverables. In our experience, three types of charts are particularly useful in evaluating CVOC profiles, assessing remediation, and conveying significance to regulators. Traditional scatter plots showing concentrations of one or more CVOC over time are essential. However, this type of chart can be difficult to follow when concentrations of many different CVOCs need to be considered, where different COVC concentrations are on different scales, or where connecting lines for different CVOC cross over one another. Changes in concentrations and relative proportions of many CVOC can be effectively visualized using stacked bar charts, where each constituent is consistently represented in the same color and the constituents are stacked in a consistent order. Additionally, transformation of CVOC from parent to degradation products and demonstration of complete degradation can be effectively visualized on combination stacked bar and scatter charts that illustrate molar proportions of each CVOC in the degradation chain and the total molar concentration, respectively.
Results/Lessons Learned
Case studies will be presented illustrating the utility of CVOC profile visualization tools to:
- Demonstrate the influence of a previously unidentified upgradient source of CVOC based on molar proportions and total molar concentrations through space and time.
- Differentiate between unique source signatures in a commingled plume. This example will specifically illustrate the utility of characteristic constituents that may be minor components of the mixture and/or present at concentrations below their regulatory standards.
- Evaluation of CVOC profiles to determine if they could or could not possibly be derived from a site’s CVOC profile.
- Demonstration of complete degradation of CVOC parent compounds and effective natural attenuation to achieve regulatory criteria.