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U.S. EPA REGION 5
WASHINGTON COUNTY
LAKE ELMO

Congressional District # 06

WASHINGTON COUNTY LANDFILL

EPA ID# MND980704738
Last Updated: November, 2011

Site Description

The Washington County Landfill (WCL) site is a municipal landfill that accepted municipal and industrial waste materials from 1969 to 1975.  The landfill was located in a former sand and gravel quarry and prior to its use for industrial waste disposal it was used as a sanitary landfill.  The landfill encompasses approximately 35 acres and contains an estimated 2.57 million cubic yards of waste.  The solid waste is comprised of 73% residential wastes, 26% commercial wastes, and 1% demolition wastes including waste from 3M Corporation.  The area adjacent to the landfill is predominantly residential, with some areas used for farming.  There is a city park located to the east and Lake Jane is 250 feet north of the property boundary.  There are aproximately 3,000 people living within a three-mile radius of the landfill.

The site was listed on the United States Environmental Protection Agency’s (EPA’s) National Priorities List in 1984

Site Responsibility

This site has been addressed through federal, state, county, and potentially responsible parties' actions.  The site is currently managed by the Minnesota Pollution Control Agency (MPCA) as part of its Closed Landfill Program.

Threats and Contaminants

In 1981, volatile organic compounds (VOCs) were detected in soil and groundwater on site.  In 1983 to 1984, VOCs were detected in off-site private wells.  In 1992, soil was sampled at the landfill and methane was detected in explosive amounts. I n 2004, perfluorochemicals (PFCs) were found in on-site groundwater and in some offsite residential wells.

Cleanup Progress

In 1975, the year that the landfill was closed, a 2-foot landfill cover was installed. In 1981, VOCs were detected in groundwater beneath the landfill and additional monitoring wells were constructed. In response to a Order by Consent from MPCA, beginning in 1984, Washington and Ramsey Counties installed a groundwater gradient control system to capture contaminated groundwater and a spray irrigation system to treat the water. 

On June 4, 1991, contracts were awarded for construction of a water supply system and residential well abandonment.  Construction of the water supply system was initiated on June 25, 1991.  An Administrative Order was issued by EPA to the counties on January 16, 1992, and amended on February 17, 1993, to continue the remedial actions.  Connection of the 10 residences with drinking water advisories to the system was completed on December 31, 1992. Connection of the remaining 71 residences was completed by June 1993. All 81 residences now have a safe drinking water supply.  In the early 1990s a gas explosion occurred due to faulty wiring and pressure build-up.  In response, fourteen extraction vents were installed in 1993 on the edge of the landfill (primarily at the western boundary) to capture methane migrating toward homes and municipal buildings and release it near the center of the WCL.  In 1996, MPCA decided to install an enclosed flare and active gas extraction system to burn the extracted methane instead of just having it released on-site.  At this time the landfill cover was also upgraded to include a geomembrane, a sand drainage layer, a rooting zone, and a topsoil layer with shallow rooted grasses.

In 1996, the MPCA and the EPA terminated the Administrative Order and put the site in long-term management under MPCA’s Closed Landfill Program. EPA then deleted the site from the NPL.  

In 2004, the MPCA sampled for chemicals known as perfluorochemicals (PFCs) for the first time and found PFCs in on-site monitoring wells and also in some downgradient residential wells.  At about this time, scientific studies had been performed documenting the risks from PFCs and improved laboratory detection limits now allowed better detection of PFCs. Since 2005, the MPCA and the Minnesota Department of Health (MDH) have sampled 404 residential wells for PFCs.  One hundred residences were placed on bottled water because they were advised by MDH not to drink their water. The MPCA placed granular carbon filters on an additional 22 residences in 2006.

On May 22, 2007 the MPCA and 3M Corporation, agreed to a Consent Order under the Minnesota Environmental Response and Liability Act (MERLA) on PFC contamination issues in Minnesota.  Further cleanup of the Washington County Landfill was included as part of the Consent Order.  The cleanup plan includes excavation of the landfill and placement of the waste into triple-lined cells onsite.  The triple lined cells will prevent further escape of any contamination from the site.  Construction began June 2, 2009 and is estimated to take three years to complete.

EPA conducts Five-Year Reviews for the site because waste is left on-site and EPA concurred with the remedy.  The latest Five-Year Review, signed in March 2009, documents that the current remedy as implemented is protective of human health and the environment in the short term because exposure pathways are being controlled.  The site will be protective in the long term following review of insitutional controls and lowering of contaminant concentrations in groundwater.

Contacts

Remedial Project Manager, U.S. EPA
leah evison (evison.leah@epa.gov)
(312) 886-2064

Community Involvement Coordinator, U.S. EPA
Don De Blasio
(312) 886-4360

Aliases

WASHINGTON COUNTY LDFL

 

Site Profile Information

This profile provides you with information on EPA's cleanup progress at this Superfund site.

 


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