Formatted Title
Enhanced Data Visualization and Analysis Approach at Former Industrial Site with Collocated ContaminationBackground/Objectives
Since 1999, a former industrial manufacturing facility in Brooklyn, New York, has been the subject of extensive environmental investigations and assessments related to a release of non-aqueous phase liquids containing polychlorinated biphenyls and releases of other contaminants including volatile organic compounds and metals. Furthermore, the site is located in a heavily industrialized area of Brooklyn that was subject to historical filling and land reclamation. As such, the site is impacted by several historical sources of contamination both on and adjacent to the site that resulted from non-site related activities (i.e., historical fill, adjacent inactive hazardous waste disposal sites). Woodard & Curran was tasked with conducting extensive remedial investigation activities to determine the extent of subsurface impacts of Site-related versus non-site related contaminants of concern to support remedial design.
Approach/Activities
Given the complexity of subsurface contamination at the site and the regulatory history, available data for the site were extensive and disparate. Several phases of investigation had been conducted over the course of more than a decade, with over 1,000 soil samples collected and analyzed for the full suite of regulated compounds. In order to standardize this extremely varied dataset, these data sources were evaluated using several python scripts and other automated processes to parse, manipulate, and ultimately consolidate the dataset into a standardized database fit for project evaluations.
Once these datasets were standardized in the project database, a series of 3-D models were prepared using Earth Volumetric Studio (EVS) representing the estimated extent of subsurface impacts for each potential contaminant of interest. These models were based on the results of kriging of the available soil concentration data for both site-related and non-site-related contaminants.
Following creation of the 3-D models, the horizontal extent of each contaminant present at concentrations above applicable standards was exported to GIS. The polygons representing the horizontal extent of impacts for each contaminant were subsequently combined and merged in several ways to determine the overall horizontal extent of site-related, non-site-related, and collocated contamination.
To determine the vertical extent of site-related, non-site-related, and comingled subsurface impacts, the data were evaluated in two distinct ways: 1) based on the kriged interpolation of concentration data in EVS, and 2) based on the elevation of the deepest sample interval from each boring with an applicable regulatory criteria exceedance. Interpolation and visualization techniques employed included kriging, inverse distance weighted interpolation, development of a triangulated irregular network (TIN) surface, and Thiessen polygons. For each approach, the vertical extent of contamination of site-related vs. non-site related compounds were visualized and evaluated in both 3-D using EVS and 2-D using GIS.
Results/Lessons Learned
This evaluation resulted in a multiple lines of evidence approach to determining the extent of site-related, non-site-related, and collocated contamination that will ultimately support future remedy design and implementation. Furthermore, the advanced data visualization techniques employed were ultimately submitted directly to the regulatory agency in lieu of more traditional 2D visualizations, and was a main factor in distinguishing site-related and non-site-related contamination, which streamlined the approval of the Remedial Investigation Report and allowed for more productive negotiations for determining remedial responsibility.