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Fact Sheet
April 2007
Operable Unit 4 Removal Action Public Availability Session, Riverfront Superfund Site, New Haven, Missouri
INTRODUCTION
The U.S. Environmental Protection Agency (EPA) Region 7 invites you to attend a public availability session scheduled for Wednesday, April 25, 2007, at the Trinity Lutheran Church, 9521 Highway 100 in New Haven to hear details about the selected cleanup action for the Maiden Lane area of Operable Unit 4 (OU4) of the Riverfront Superfund Site. Cleanup objectives for OU4 are designed to minimize migration of volatile organic compounds (VOCs) from impacted soils into underlying ground water and to contain and treat perched water above and within the upper part of the weathered bedrock.
Representatives from EPA, the U.S. Geological Survey, and the Missouri Department of Natural Resources will be on hand to answer questions related to the selected cleanup action.
BACKGROUND
In 1986, tetrachloroethene (PCE) was detected in two public-supply wells
in the northern part of the city of New Haven.
Following the discovery of the PCE contamination, two new public-supply
wells were installed in the southern part of the city. Based on
information obtained through site investigations, EPA divided the Riverfront
Site into six operable units.
OU4 was designated in 2000 after PCE was detected in a bedrock monitoring well south of closed public well W2. OU4 encompasses much of the east half of the city north of Highway 100.
THE CONTAMINATION
To delineate the presence of PCE in ground water at OU4, EPA installed a total of nine monitoring wells in the bedrock and overlying soils in the Maiden Lane area. PCE concentrations as high as 9,100 micrograms per liter (ug/L) have been detected in groundwater samples collected from the OU4 monitoring wells. The highest levels of contamination are within or immediately beneath the upper sandstone bed and about 130 to 160 feet beneath ground surface.
EPA also collected soil samples to determine the extent and location of PCE contamination in the Maiden Lane area. Soil borings collected in this area confirmed substantial levels of PCE in 102 of 103 samples collected. The footprint of soil contaminated with PCE in this area was estimated at 3,800 to 5,700 square feet depending upon the soil sample depth. The largest extent of contamination is in the interval of 12 to 18 feet below ground surface. Contamination extends through the overlying soils into the top of the weathered bedrock. The calculated total volume of contaminated soil is approximately 2,500 cubic yards.
PROPOSED REMOVAL ACTION
On February 22, 2007, EPA signed an Action Memorandum to address PCE contamination at OU4. The removal action will be funded by EPA since no potentially responsible party has been identified. EPA’s proposed removal action involves the injection of a chemical oxidant at several locations (up to 127) at the Maiden Lane area within approximately a 3,600 square-foot area downward of the source area. The oxidant will be injected directly into the soil. Ground water monitoring will be performed to determine if a second injection of chemicals is needed to reduce the amount of PCE in the shallow ground water.
Public Availability Session
You are invited to attend a public availability session to hear about EPA’s plans for Operable Unit 4.
Wednesday, April 25, 2007
7:00 p.m. - 9:00 p.m.
Trinity Lutheran Church
9521 Highway 100
.3New Haven, Missouri
For more information, please contact:
Dianna Whitaker
U.S. EPA Region 7
901 N. 5th Street
Kansas City, Kansas 66101
Toll-free 1-800-223-0425
whitaker.dianna@epa.gov
ADDITIONAL INFORMATION
The Action Memorandum for OU4 and other site-related documents are part of the Administrative Record file, available during regular business hours at the following locations:
New Haven Regional Library
109 Maupin
New Haven, Missouri
EPA Region 7
901 N. 5th Street
Kansas City, Kansas
If you have questions or need additional information, please contact:
Dianna Whitaker
Office of External Programs
U.S. EPA Region 7
901 N. 5th Street
Kansas City, Kansas 66101
Phone: 913-551-7003 or
Toll Free: 1-800-223-0425
whitaker.dianna@epa.gov
