Water Protection Activities in Washtenaw County

Challenge # 7: Gelman Sciences Inc. 1,4-dioxane
Between 1968 and 1986, Gelman Sciences, Inc., (sold to New
York-based Pall Corp. in 1997, now known locally as Pall Life
Sciences) discharged hundreds of thousands of pounds of 1,4dioxane
into the local environment at their facility near Liberty
and Wagner Roads in Scio Township. 1,4-dioxane is suspected
of causing health problems and is classified by the U.S.
Environmental Protection Agency (EPA) as a probable human
carcinogen. The persistent pollutant was discharged into
lagoons, wetlands and unlined pits. It was also dispersed
through spray irrigation and deep-well injection. 1,4-dioxane
was released in combination with other compounds used in the
manufacturing of medical filters.
In 1987, although the company had halted its use and discharge
of 1,4-dioxane, it was discovered that a large underground
storage tank had been leaking. The contamination percolated
down into the aquifer northwest of Ann Arbor (Map 7). The
plume of 1,4-dioxane headed east in the general direction of
the Huron River and directly underneath the City of Ann
Arbor.
Approximately 124 private water supply wells have been
connected to the City of Ann Arbor water supply as a result of
the contamination. State funding provided since 1995 has
allowed for the monitoring of
drinking water wells affected
or threatened by groundwater
contamination from this site
and others. Washtenaw
County was the first county
in the State to participate in
this program.
What protection
activities address the
challenge of
Pall Life Sciences?
Pollution Prevention
Well Restricted Areas
24
The plume of contamination has lead to the court-ordered
creation of a groundwater use restriction area, or “Prohibition
Zone” (PZ), in which drinking water wells are prohibited from
being drilled and existing wells are required to be properly
abandoned (Map 7). Additionally, one municipal water supply
well, the City of Ann Arbor’s Northwest Supply Well, has been
taken out of service after a 2001 positive test result for 1,4dioxane.
As part of the remediation effort, Pall Life Sciences has treated
and discharged nearly 3 billion gallons of groundwater since
1997. The groundwater is collected at extraction wells and
pumped to a treatment center. The treatment uses ozone and
hydrogen peroxide (H2O2) to reduce the levels of 1,4-dioxane
to below the limits of acceptable criteria. Treatment removes at
least 99% of the contaminant and discharges water with a 1,4dioxane
concentration of less than 10 parts per billion. The
treated water is released into a tributary of Honey Creek, which
discharges into the Huron River. This discharge is upstream of
the City of Ann Arbor’s main water intake at Barton Pond.
Currently, the health risk to residents is minimized due to
ongoing remediation and monitoring stations. However, the
1,4-dioxane plume of impacted groundwater has spread to an
area nearly three miles long by one mile wide and continues to
threaten drinking water supplies.
Gelman Science Inc. 1,4-dioxane Response Objective:
Minimize the exposure to and consumption of water with
elevated levels of 1,4-dioxane in Washtenaw County.