Region 5 Superfund (SF)

U.S. EPA REGION 5
WASHINGTON COUNTY
LAKE ELMO

Congressional District # 06

WASHINGTON COUNTY LANDFILL

EPA ID# MND980704738
Last Updated: December, 2008

Site Description

The Washington County Landfill is located in the City of Lake Elmo in Washington County, Minnesota. The site is located near a sparsely populated residential development with some farmland in the area. The original permitted area for the landfill was 110 acres with a fill area of 35 acres that contains approximately 2,570,000 cubic yards of mixed municipal, industrial and construction wastes.

From 1969 to 1975, Washington and Ramsey counties (the counties) operated the landfill until operations were discontinued. In 1975, a clean soil cap was placed on the landfill. In 1981, groundwater monitoring indicated the presence of elevated concentrations of volatile organic compounds (VOCs) and some heavy metals in onsite monitoring wells and offsite residential wells. In 1983, the counties installed a pump and treat system to reduce any potential groundwater contamination from the landfill.

Site Responsibility

This site is being addressed through federal, state, county, and potentially responsible parties' actions.

Threats and Contaminants

The soil and groundwater are contaminated with VOCs and just the groundwater is contaminated with perfluororchemicals (PFCs).   PFCs were only recently identified as a contaminant of concern at this site.  VOCs found in residential wells are below MCLs.  However, there are no MCLs for PFCs.  Adverse health effects may exist for people who accidentally ingest or come into direct contact with contaminated groundwater and/or soil; however, the immediate threats have been addressed because residents have been provided with an alternate water supply as discussed, below.

Cleanup Progress

 In 1984, a consent order was signed between the counties and the Minnesota Pollution Control Agency (MPCA) for the counties to perform cleanup activities. In 1983 and 1984, alternate drinking water supplies were provided to affected residences, and Ramsey and Washington counties installed a groundwater extraction and treatment system. In September 1990, a remedy was selected to supply drinking water to residents of 10 homes in Lake Elmo who had received Minnesota Department of Health advisories against using their existing well water for drinking or cooking. The remedy called for these homes to be connected to the city of Oakdale's public water supply system. Construction was completed in 1992.

In early 1992, the U. S. Environmental Protection Agency (EPA) issued a unilateral administrative order (UAO) to the counties, requiring them to continue cleanup activities under EPA oversight. Cleanup remedies selected included: installing and operating a groundwater control system at the site; providing safe drinking water supplies for affected residences; monitoring the landfill and the effectiveness of the groundwater gradient control system; instituting appropriate landfill security and safety procedures; and implementing a landfill closure plan. The groundwater gradient control system is in operation, and monitoring of the groundwater will continue until the long-term effectiveness of the remedy is confirmed.

All construction at the site is completed, and the site was deleted from the National Priorities List in May 1996. A five-year review was completed on April 16, 1999. The second five-year review was completed in April 2004 and concluded that the remedy remains protective of human health and the environment.

After the 2004 five-year review was completed, 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 have been placed on bottled 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 landfill will be dug-up and placed into triple-lined excavated boxes onsite. The triple lined boxes will prevent further escape of any contamination from the site. Construction is scheduled to begin October 2008 and is estimated to take three years to complete.

Contacts

Remedial Project Manager, U.S. EPA
margaret gielniewski (gielniewski.margaret@epa.gov)
(312) 886-6244

Community Involvement Coordinator, U.S. EPA
Don De Blasio
(312) 886-9749

Aliases

WASHINGTON COUNTY LDFL

 

Site Profile Information

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