Environmental Engineering Reference
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about 11 million pounds of methyl chloroform to the atmosphere and transferring about 1 million
pounds to waste-handling facilities (USEPA, 1995b). The quantities of 1,4-dioxane reported in the
1993 Toxics Release Inventory, about 11,000 lb, probably understate the releases associated with its
likely presence as a stabilizer of methyl chloroform. The 1995 Toxics Release Inventory also reports
1,4-dioxane for only four facilities, but lists more than 100,000 lb of 1,4-dioxane transferred and
about 5000 lb released.
2.3.7 A IRCRAFT D EICING F LUID AND A NTIFREEZE
Before 2000, 1,4-dioxane was an ingredient or impurity in aircraft deicing l uids and antifreeze
solutions. The Air Transport Association reportedly listed the following components of deicing
l uid in 1994: ethylene glycol or propylene glycol, water, surfactants (wetting agents), corrosion
inhibitors (including l ame retardants), pH buffers, dyes, 1,4-dioxane, and complex polymers as
thickening agents (USEPA, 2000). Glycol deicing formulations were previously used to treat airport
runways. Because 1,4-dioxane was an impurity as residual solvent carried over from production of
glycol, past uses of glycol deicing agents could leave trace levels of 1,4-dioxane in soil and ground-
water near runways. MSDS for aircraft deicing l uids list a trace presence of 1,4-dioxane (0.0022%
or 22 mg 1,4-dioxane per liter of deicing l uid) as an impurity of glycol compounds (Union Carbide,
1989). 1,4-Dioxane was also used as a wetting and dispersing agent but composed less than 0.5 mg/L
of deicing l uids (USEPA, 2000). Others report that past levels of 1,4-dioxane in deicing l uids were
on the order of 3 mg/L (Gelman Sciences, 1989a). 1,4-Dioxane can be detected in glycols in the low
part per million range (Pundlik et al., 2001).
To reduce groundwater contamination, deicing l uid manufacturers have removed 1,4-dioxane
from their formulations (USEPA, 2000). The main deicing agents used today are urea and calcium-
magnesium acetate, more commonly known as “road salt.”
Many brands of automotive antifreeze list 1,4-dioxane as an ingredient or a component at less
than 0.0086% (86 mg 1,4-dioxane per liter of antifreeze l uid) (Old World Automotive Products,
Inc., 20 01). 1,4 -Dioxane is also listed as a trace component of recycled antifreeze at less than 0.0 04%
(40 mg/L) (FPPF Chemical Company, Inc., 2006). Analysis of consumer antifreeze products found
1,4-dioxane present at concentrations ranging from 0.1 to 3.4 mg/L (Gelman Sciences, 1989c).
Analysis of radiator l uid boil-over verii ed the presence of 1,4-dioxane at up to 22 mg/L (ATSDR,
2005). The higher concentration of 1,4-dioxane in radiator boil-over compared to the concentration
in antifreeze products suggests that heating ethylene glycol in a radiator, coupled with possible
acidii cation from metal oxides, could lead to formation of 1,4-dioxane, as described in Figure 2.3 .
In an effort to draw attention to the potential widespread contamination by 1,4-dioxane from
antifreeze and deicing l uids, Charles Gelman, the CEO of Gelman Sciences, testii ed at a State of
Michigan hearing that sample results from puddles of car radiator boil-over contained high levels of
1,4-dioxane (Judge, 1988). Gelman's letters cautioned that 1,4-dioxane could pollute groundwater at
rest stops and wherever winterization practices for plumbing systems in summer cottages included
i lling pipes with ethylene glycol to prevent freezing during the winter. Flushing out the lines the
following summer would cause 1,4-dioxane to l ow through septic systems. The same issue was
raised for winterizing recreational vehicles and large boats (Gelman Sciences, 1989b).
2.3.8 A DHESIVES
A number of glues and adhesives were prepared with a chlorinated solvent base to facilitate spread-
ing and drying. 1,4-Dioxane is present in some glues as a solvent and in others as a stabilizer of
methyl chloroform. The National Library of Medicine Household Products Database lists a brand of
wood parquet l oor paste as containing 0.5% 1,4-dioxane; an adhesive for afi xing trim and detailing
to automotive surfaces is listed as containing 1-3% 1,4-dioxane (DeLima Associates, 2004; HSDB,
2006). Adhesives containing methyl chloroform can also be expected to contain trace amounts of
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