Technological Context of the 1986 Trial

Often it is difficult for people who did not live during the time period of the Woburn Toxic Trial to appreciate the limits of technology in the mid-1980s. The purpose of this webpage is to describe the state-of-the-art in computer computations for ground-water modeling and the detection of dilute concentrations of dissolved organic compounds like TCE and PCE using gas chromatography - mass spectrometry.


IBM AT computer, vintage 1985

It is important to put the computational efforts of the expert hydrogeologic witnesses in the trial into the context of the state-of-the-art in 1985-1986. IBM introduced the personal computer (PC) in 1981. The original PC had no hard drive, ran at 4.77 MHz, had 64 KB RAM, software operated under 256 KB, and had a monochrome monitor (green was normal, amber was more cool). It was magnificent, but by today's standards it was the equivalent of a Model T Ford. In 1983, IBM came out with the XT model, which had the first hard drive, a walloping 10 MB, but still used a monochrome monitor. In late 1984, IBM began selling its AT model, which ran at 6MHz, had a 20MB hard drive, and had a color videocard to support color monitors. At that time, it was the bees knees.

The computer modeling of the groundwater flow system near wells G and H that was presented during the 1986 trial Dr. John Guswa (W.R. Grace) and during the depositions of Dr. George Pinder (plaintiffs) by was done using IBM AT machines. The software that Dr. Pinder ran, the Princeton Transport Code, was written in Fortran by he and his graduate students. The software Dr. Guswa ran was an early version of the U.S. Geological Survey MODFLOW code written by Peter Trescott (Trescott, 1976), that was linked to a propriety solute transport code called FTWORK (GeoTrans, 1982).

Today's machines run at speeds of 2.6 GHz or more, almost 500 times faster than the IBM AT, and have nearly unlimited memory. The limited speed and memory of the IBM AT machines, only enabled the models constructed for the trial to have a few tens of nodes in the x and y dimensions and a couple of layers in the z dimensions. The models took hours and hours to run. The simulated water levels and contaminant concentrations produced by the models were contoured by other programs. The magnificent groundwater simulation software that is used today, like Groundwater Vistas and Visual ModFlow, were not developed until and 1990s after most of the memory limitations of the early PCs were removed. So, when you look back to 1986 and read the expert testimony given in the trial, be sure to look back considering the state-of-the-art in computer processing and computer graphics at that time.

Gas Chromatography - Mass Spectrometry

Vintage GC/MS, circa 1970

The use of mass spectrometer as the detector in gas chromatography began in the 1950s. The early machines were big, bulky, fragile, and sufficiently expensive to be limited to the budgets of federal laboratories and prominent universities. The development and miniaturization of CG/MS coincided, fortuitously, with the advent of laboratory computers and later personal computers. The ability of these computers to process the data was critical to the widespread use of the technique and the lowering of production costs.

In the 1970s, U.S. EPA promulgated a number of environmental laws that required the detection of minute amounts of dissolved organic compounds in water. GC/MS was the perfect tool but many of these compounds lacked a reference spectrum for comparison to measured spectra from water samples. At that time, analysis of an unknown solvent could take 10 - 20 minutes. Today, top-of-the-line machines complete the work in a minute or less.

GC/MS machines and analysis has evolved tremendously since the two water samples from Woburn wells G and H were analyzed in May 1979. At that time, Massachusetts was one of the few states using a GC/MS for environmental work and its common use by commercial laboratories was still many years away.