Forensic Applications for 1,4-Dioxane and Solvent Stabilizers - Environmental Investigation and Remediation - page 417

9 Forensic Applications

for 1,4-Dioxane and
Solvent Stabilizers

Thomas K.G. Mohr

In the town of Solventville, a printing shop, a former dry cleaner, an electrical utility substation with
several large transformers, and a printed circuit board manufacturer are all located within a short
distance of each other. The neighboring gas station investigates a fuel tank leak and discovers
perchloroethylene (PCE) in groundwater samples. The regulator suspects that the PCE originated
from the printed circuit board manufacturer, which is located up-gradient from the gas station. The
electronics i rm retains a consultant, namely you, to advise it of its potential liability in the PCE
spill. Your initial review shows that PCE was used in varying amounts at different times at all the
four facilities, and even though two facilities are cross-gradient of the current known occurrence at
the gas station's monitoring wells, sewer lines and storm drains may have provided a horizontal
conduit through which PCE could have migrated. How will you proceed? It is time to open your
environmental forensics toolbox and see what you have got to work with. Solvent stabilizers are a
potentially useful forensic tool; however, very little work has been published documenting their
application in completed studies.
An all-encompassing dei nition for the widely used term “environmental forensics” is found in
the dei nitive primer from two leading authors on the subject:

Environmental forensics is the systematic and scientii c evaluation of physical, chemical, and historical
information for the purpose of developing defensible scientii c and legal conclusions regarding the
source or age of a contaminant release into the environment. *

Forensic investigations into environmental contamination are usually oriented toward attributing
responsibility to parties who used and released a contaminant and must therefore share in the bur-
den of investigation and remediation (Murphy and Morrison, 2007). Environmental forensic inves-
tigations often focus on cost allocation; however, contaminant hydrogeologists can derive many
other dividends by applying environmental forensic techniques to verify and enhance their site
conceptual model.
Chlorinated solvents have been the subject of many forensic investigations. Methods to distin-
guish sources of solvents include the following:

• Mapping ratios of the solvent to its breakdown products

• Correlating historical operations to the general pattern of solvent usage constrained by

regulations, equipment developments, and markets
Back-calculating the timing of a release from the length of a plume and rates of ground- •

water l ow

* From the foreword to Environmental Forensics—Contaminant Specii c Guide by Robert D. Morrison and Brian L.
Murphy (Morrison and Murphy, 2006).

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