The Visualization of PCB Contamination in the Housatonic River Sediment

Lee R. Minardi, Damian R. Siebert

Department of Civil and Environmental Engineering

Tufts University

Introduction

This Web site highlights the results of a research project aimed at developing a better method for visualizing the location and intensity of PCB sedimentation in the Housatonic River. Commercial CAD software was used to model geographic bounds of the river, the surrounding terrain and signposts that indicate the location, depth and concentrations of PCB sediments. An animated fly-by of the model yields an effective tool for the visualization of complex data.

Background

The Housatonic River winds south from Vermont through Western Massachusetts and the town of Pittsfield on its way to Connecticut and eventually to Long Island Sound and the Atlantic Ocean. During much of the past 50 years, the General Electric plant on the north side of town, adjacent to the river, produced transformers. A byproduct of the manufacture of the inert plastics required for the production of the transformers was about 39,000 pounds of polychlorinated biphenyls, or PCBs. The GE facility released the PCB contaminated wastewater into Silver Pond and the Housatonic River. Although the factory has long been closed, the PCBs still remain in the riverbed sediment for most of the river's downstream expanse within Massachusetts from the plant in Pittsfield to Woods Pond in Lenox.

Since 1981, several series of PCB measurements were taken along the river from the GE plant to Woods Pond, a distance of about seven miles. Measurements were performed in 1982, 1991, 1994 and 1995. The PCB measurements were recorded at approximately 6 inch intervals below the river bed. Each series consisted of a different number of measurements, at different locations and to differing depths. The data was originally presented in a series of tables and one long map of the river with embedded tables to indicate PCB levels.

Objective

The objective of this project was to clearly present the complex PCB contamination data of the Housatonic River. We sought to develop a technique in which the intensity of PCB contamination, and its variation with depth below the riverbed, could be readily identified by concerned citizens as well as professionals directly involved with the cleanup of the river.

Results

The primary results of the PCB visualization project is a computer graphic animation that simulates a flight south along the Housatonic River from the former General Electric facility to Woods Pond. Signpost are located along the river to indicated where PCB measurements were taken. The signpost are color coded to indicate the year the data was recorded. In addition, a system of red bars on a white background indicate the quantity of PCBs and their depth below the riverbed.


Click the image for
a signpost summary.
Click here for a detail presentation of how to interpret the PCB measurement signposts

Animation
A viewing of the animation provides a quick assessment of the distribution of data collection sites. The study of individual frames of the animation yields an increased understanding of many interrelated parameters of the PCB distribution and the year in which the data was taken. Click the image to view a mini-animation.

Detailed Still Images

The map below right is a birds-eye view of the seven miles of Housatonic River that were the subject of this research. The small images on the left may be enlarged by clicking on them to view a sample of full size still images from the complete animation. In the enlarged still images you can readily see the locations of the highest concentration of PCBs. Note that full width red bars indicate levels of 100 ppm or greater. Gray background signpost are used for the oldest measurements (1981). The green and black striped signs display the most recent data.
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Conclusions

An interactive examination of the Housatonic River animation has been found to be an effective visual aid for providing the viewer with a qualitative assessment of complex data. The animation provides a means for viewing data relative to a geographic area that is long and narrow which would otherwise be difficult to interpret in individual static images. The color coded signposts proved effective for quickly identifying many details that were difficult to comprehend from the tables of raw data. Among these parameters are the density of measurements along the river over time, the distribution of the relatively higher levels of PCBs along the river, and the migration, or lack of migration, of PCBs down river and deeper into the river bed.

Acknowledgments

Part of this activity was funded by the Technical Outreach Services for Communities (TOSC) program under a grant from the Environmental Protection Agency Research Center Federal Regions 1 & 2.

The authors would like to thank professors Lewis Edgers, David Gute and Anne Marie Desmarais of the Civil and Environmental Engineering department at Tufts University and Tim Gray of the Housatonic River Initiative, Pittsfield, Massachusetts for their assistance in this project.