Gelman Sciences Dioxane Project;
Ann Arbor, MI

Unit E Aquifer

HISTORY
Contamination was discovered in the Unit E Aquifer in the spring of 2001 during an investigation of the Western System. It was discovered that there was no confining layer of clay separating the unit E Aquifer from the unit D2 Aquifer. The exact locations of the links causing the contamination of Unit E by Unit D2 are not known although one link is near the western extent of contamination in the Unit D2.

Since contamination was discovered 29 monitoring wells have been installed to determine the extent of the contamination. The width of the plume has been determined to be over 1000 feet.

LOCATION
The Unit E Aquifer is located just above the bedrock, nearly 200 ft below ground surface, in an area extending from Parkland Plaza to Worden Street and east of Veterans Park.

CURRENT STATUS
Two extraction wells have been operating since May 2001. They are removing about 175 gallons per minute of contaminated groundwater. The contaminated groundwater is being treated and discharge to the Honey Creek Tributary. A feasibility study will be submitted shortly to the Michigan Department of Environmental Quality. It will examine the options for handling the contamination in the Unit E Aquifer. Upon approval of the feasibility study PLS will submit a work plan and a selected treatment option to the Michigan Department of Environmental Quality for approval.

Unit C3 (Core Area)
Unit D0 (Western System)
Unit D2 (Evergreen System)
Unit E Aquifer