Case Studies of 1,4-Dioxane Releases, Treatment, and Drinking Water Contamination - Environmental Investigation and Remediation - page 382

contaminants from the plume that spread eastward into the deep Unit E aquifer. Judge Shelton
noted, “It will never be possible to extract all of the 1,4-dioxane from this deep aquifer and the
geology is such that it will ultimately end up in the Huron River and be diluted far below currently
acceptable standards. But the goal must be to remove as much of the contaminant as possible, as
quickly as possible, so that the ultimate dilution will take place with minimal impact on the water
resource” (Shelton, 2004).
The court's unusual solution was to allow the leading edge of the 1,4-dioxane plume to migrate
through Ann Arbor unabated. The court ruled that this option is allowed by Michigan law, pro-
vided unacceptable exposures to human health and the environment are prevented, including an
institutional control to prevent use of the groundwater in the expected path of the Unit E plume
(Shelton, 2004). This ruling led to the creation of the PZ, which is the antithesis of the antidegrada-
tion policy used for groundwater resources protection elsewhere in the United States. Nevertheless,
MDEQ has effectively eliminated exposure and ensured water supply reliability, while P/GSI has
continued its substantial progress with remediating this massive 1,4-dioxane plume and monitor-
ing its migration.
In July 2008, Charles and Rita Gelman donated $5 million to the University of Michigan's Risk
Science Center, which promotes the application of multidisciplinary skills to the study of the
diverse health hazards that people face. The university expects the gift to position its Risk Science
Center to become the nation's premier center for assessing, quantifying, and communicating risks
to public health. The gift also supports graduate student fellowships and the hiring of two addi-
tional faculty members in the i eld and establishes a named professorship for a senior researcher.
The Gelmans announced that their vision is to “help inform industry, government and the public
about how to properly assess the benei ts and hazards posed by technology (and chemicals in par-
ticular) in our society.” Mr Gelman believes that settlement of the P/GSI 1,4-dioxane cases would
have come far earlier if a neutral entity such as the U-M Risk Science Center had existed (University
of Michigan, 2008).
8.4 FORMER AMERICAN BERYLLIUM COMPANY, TALLEVAST, FLORIDA
The former American Beryllium Company (ABC) site in Tallevast, Florida, is an example of the
impact that the late discovery of 1,4-dioxane in a cleanup can have on-site investigation, remedia-
tion, and community relations. The bulk of the information presented herein was derived from the
very comprehensive website for the project ( http://www.tallevast.info/ ) and from the Florida
Department of Environmental Protection (FDEP) website ( http://www.dep.state.l .us/ ).
Located in Florida's Manatee County, Tallevast traces its roots back to the 1890s, when shacks
were built there for a community of African-American laborers. The laborers who i rst lived in
Tallevast worked tapping sap from the local long-leaf “slash” pine forests and boiled it to make
turpentine for use in the nation's shipyards and harbors. Residents of this “turp camp” also grew
sugarcane, celery, and strawberries in area i elds or worked in orange groves or on dairy farms
(Lerner, 2008). At present, Tallevast is a blend of single-family residential homes and light com-
mercial and industrial development (Cilek et al., 2004). Tallevast is located between Bradenton and
Sarasota and less than 2 miles from Florida's west coast.
8.4.1 G EOLOGIC S ETTING
Tallevast is situated in north-central Manatee County, in the terraced coastal lowlands physiographic
province, a featureless plain extending to the Gulf of Mexico. The stratigraphy in the area consists
of sandy sediments overlying a sequence of limestones, clays, and sandy limestones. The near-
surface geology to a depth of 18 ft in the vicinity of the American Beryllium site consists of an
upper unit of undifferentiated sandy and silty sediments of Holocene to Pliocene age and a lower
undifferentiated carbonate unit of the Miocene Arcadia Formation extending to a depth of 300 ft