Groundwater in the Great Lakes Basin

Although significant cleanup efforts have been made,
the current national backlog is still more than 106,577
with 25,392 of these sites yet to be addressed (U.S.
EPA, 2008a). Additionally, more than 7,500 new LUST
sites are found each year (U.S. EPA, 2007c). The Federal
Emergency Management Agency knows of at least 150
tanks storing more than 5,000 gallons of diesel fuel,
which they are responsible for, that could be leaking
contaminants into groundwater (Sullivan, 2008). Other
sources indicate that there may be an additional 3.8
million non-federally regulated and orphaned USTs
(Sierra Club, 2005) resulting in an overall total of 5
million USTs in the U.S. USTs that are exempt from
federal regulations are not regulated and therefore do
not undergo routine inspections or updates. These
include, but are not limited to (U.S. EPA, 2002; Rothe,
2003):
• Tanks located on residential or farm properties
with a capacity of less than 1,100 gallons (4,164
litres) containing petroleum products to be used as
motor vehicle fuel for non-commercial purposes
• Tanks for storing heating oil for use on the
premises where the tank is located
• Flow-through process tanks
• Septic tanks
• Storm water or wastewater collection systems
• Surface impoundments, pits, ponds or lagoons
• Storage tanks located in an underground area such
as a basement, cellar, mine, shaft, if the tank is on
or above the surface of the floor
• Emergency spill and overflow tanks which are
promptly emptied
• Underground storage tank systems with a capacity
of 110 gallons or less
• Underground storage tank systems that contain a
de minimis concentration of regulated substances
Assuming that 25% of all USTs are leaking
(MacRitchie, Pupp, Grove, Howard and Lapcevie,
1994; Alsip, 1993; IJC, 1993), results in a LUST count
of 1,250,000, significantly higher than indicated by the
tally for federally regulated USTs alone.
CONTAMINATION DANGERS
Although petroleum products and additives (e.g.,
methyl tert-butyl ether or MTBE) are generally the
major concern at LUST sites, leaking solvents (e.g.,
TCE and PERC) are also a serious issue regarding
groundwater contamination. Many of the substances
stored in USTs are not only dangerous but also highly
mobile in soils and aquifers. Toxic chemicals present
in LUSTs include, but are not limited to, BTEX,
MTBE, methylcyclopentadienyl manganese tricarbonyl
(MMT), cadmium, naphthalene, lead, PCBs, 1,2-dichloroethene
(DCA) and 1,2-dibromoethene (EDB) (Braves,
2003; Galloway, 2004; Falta, Bulsara, Henderson and
Mayer, 2005; Sierra Club, 2005). Health effects caused
by these chemicals include damage to various vital
organs; damage to the immune, respiratory, reproductive,
endocrine and other systems; various health effects
to developing children and cancer (Sierra Club, 2005).
Some efforts are being taken by refineries to help
reduce toxic additives. Canada’s largest refineries have
voluntarily stopped using MMT even though it is still
permitted by law (Galloway, 2004). However, states
are not required to follow rigid guidelines when testing
for all contaminants present at LUST sites as long as
procedures and regulations meet U.S. EPA standards.
This is causing difficulties in determining the degree
of contamination of various substances (Falta et al.,
2005). For example, compounds of specific concern
include EDB and DCA, which were additives to leaded
gasoline. Both are designated as probable carcinogens,
and EDB has been found to be an exceptionally strong
carcinogen in animals. They are noted as being “among
the most commonly detected contaminants in U.S.
public drinking water systems that rely on groundwater”
(Falta et al., 2005). However, unless specified
in the sampling program, they are generally not tested
for in site analyses, potentially leaving thousands of
contaminated sites (Falta et al., 2005). In a recent study
of LUST sites 59% have groundwater contaminated
with EDB (Falta et al., 2005).
METHYL TERT-BUTYL ETHER
MTBE is a gasoline additive used to oxygenate fuel and
reduce emissions (GAO, 2007). MTBE is highly mobile
and persistent in the environment, resulting in the
development of large contamination plumes (Falta et
al., 2005) that often contaminate groundwater (GAO,
2007). Because MTBE is water soluble, it can easily
contaminate groundwater, seeping out from USTs and
transmission lines (Larini, 2008). For example, as of
2005 MTBE has been found in more than 1,861 public
water supply systems in the U.S., up from 1,500 in
2003 (Environmental Working Group, 2005). Even
very low MTBE concentrations render groundwater
unsuitable for drinking, and many municipal wells
have been closed as a result. A survey by the U.S.
Geological Survey found 300 out of 3,964 sampled
groundwater sites to be contaminated with MTBE. 13%
of contaminated samples were found in urban areas
(Moran, Zogorski and Squillace, 2005). No national
standard has yet been set regarding acceptable levels
(GAO, 2007). Due to health concerns many states have
banned MTBE including seven of the eight Great Lakes
States (Bauman, 2003). In 2006 oil companies stopped
using MTBE (Mouawad, 2008). However, MTBE is
still being discovered at LUST sites in states with bans
(Martinson, 2003) and is also being found at LUST
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