3M Woodbury Site
The 3M Woodbury Site is located approximately six miles south of Interstate 94 along the border of Cottage Grove and Woodbury (between Co. Rd 19/Woodbury Drive and Lamar Ave just north of 67th Street). Since 1992, the site has been in the Voluntary Investigation and Cleanup (VIC) Program at the Minnesota Pollution Control Agency (MPCA).
The site consists of three disposal locations used for disposal of solid waste, industrial solvents and acids from 3M's Cottage Grove and Saint Paul manufacturing facilities during the 1960s. Woodbury and Cottage Grove residents also used the site for dumping municipal waste (such as household, automotive, construction, and commercial debris). In 1966 isopropyl ether, an industrial solvent, was discovered in a shallow well on a nearby property. This prompted further investigation of the site and more extensive well testing for area residential wells. A variety of hazardous substances, particularly volatile organic compounds (VOCs), were found at the site in both the soil and groundwater. However, no other drinking water wells were found to be contaminated.
3M has taken voluntary actions since the late 1960's to address soil and groundwater contamination. Some of the actions taken include: excavation of disposal trenches and burning waste on site, re-grading the property with a layer of compacted soil over disposal areas to limit leaching of the wastes; fencing certain areas around the site; regular testing of on-site and off-site groundwater monitoring wells, barrier wells, and residential wells; and installation of four groundwater pump-out wells to contain the spread of contaminants in the groundwater. This pump-out system carries the extracted groundwater by pipeline to the 3M Cottage Grove plant where it is used for non-contact cooling water, treated, and then discharged to the Mississippi River.
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PFCs at the 3M Woodbury Site
The 3M Woodbury Site was used as a disposal site for perfluorochemical (PFC) waste. PFCs are a family of manmade chemicals that have been used for decades to make products that resist heat, oil, stains, grease and water. They were produced in the late 1940s until 2002 by 3M at its Cottage Grove facility.
In spring 2005, low levels of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) were detected in the groundwater pump-out system at the 3M Woodbury site, prompting an investigation of nearby residential wells by MDH and MPCA to determine if PFCs were migrating from the dump in groundwater. PFOS and PFOA were not detected in any of the private wells.
However, in spring 2006, the MDH Public Health Laboratory expanded its PFC analytical method to include five additional PFCs. Of the five, perfluorobutanoic acid (PFBA) was found to be widespread in the groundwater south of two other 3M waste disposal sites, the former Washington Co. Landfill (link) in Lake Elmo and the Oakdale Dump (link), and extending south into the city of Woodbury. In late 2006 to early 2007, additional sampling of monitoring wells at the 3M-Woodbury Disposal site and private drinking water wells near the site also detected PFBA.
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PFCs in South Washington County
In December 2006, as part of a regional evaluation of PFBA in groundwater, the city wells in Cottage Grove, Newport, and St. Paul Park were sampled for PFCs. PFBA was detected in all of the wells tested but neither PFOA nor PFOS were found at that time. Since then, as the MDH Public Health Laboratory has improved its testing method and can detect very low concentrations of PFCs, trace levels of PFOA and other PFCs have been detected in some of the Cottage Grove, Woodbury, Newport, and St. Paul Park city wells, but all below MDH drinking water criteria.
It is likely the PFCs in these wells comes from more than one source. Groundwater in this part of Washington County flows to the south and southwest; the PFCs in the Woodbury wells likely comes from the 3M-Oakdale and Washington County Landfill sites, while the PFCs in the Cottage Grove, Newport, and St. Paul Park wells likely come mainly from the 3M-Woodbury Disposal Site, but some portion may also come from the two northern disposal sites, and possibly other unidentified releases related to fire-fighting activities (See Aqueous Film Forming Foams and PFCs).
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What Actions Are Being Taken?
MDH and MPCA worked together to sample over 1,100 private wells in south Washington County to determine the extent of the groundwater contamination and identify any wells that exceed MDH drinking water criteria. Over 26 drinking water advisories have been issued to private well owners in Cottage Grove (primarily in the area south of Highway 10 and west of the 3M-Cottage Grove plant).
MDH and MPCA continue to monitor approximately 300 wells in this area annually to track the PFC plume. In general, PFC concentrations have remained quite stable over time. How often a well is sampled is based on the concentration of PFCs detected in that well and nearby wells. In some areas with very low PFC levels, two or three wells are used as "sentries" to track water quality, rather than sampling all of the wells in that area. All homes where PFCs exceed MDH drinking water criteria are provided with GAC filter systems that are monitored and maintained by MPCA. Wells located along the edges of the PFC plume are also sampled to monitor any changes in the size and concentration of the plume.
In 2008, 2010, and 2014, MDH completed biomonitoring studies of selected residents in Cottage Grove, Lake Elmo, and Oakdale who were known to have been exposed to PFOA and/or PFOS in their drinking water. The average concentration of PFCs in the participants' samples were higher than the averages for the general U.S. population. The studies also showed that over time, as the participants drink treated water, the PFC concentrations in their bodies decreased. More information about the biomonitoring studies can be found at PFC Biomonitoring: East Metro.
In 2009-2011, 3M completed additional cleanup actions at the 3M-Woodbury Disposal Site. This included excavation of contaminated soils and off-site disposal in lined containment facilities, improvements to the pump-out system to ensure contaminated groundwater is contained on-site, and installation of additional wells to monitor the groundwater at the site. More information about these actions can be found on the MPCA webpage Perfluorochemical (PFC) waste sites.
Currently, the site groundwater pump-out system is extracting over 4 million gallons of groundwater per day. As the population of south Washington County increases, so does the demand for water. 3M is working with MPCA, MDH, and the cities of Cottage Grove and Woodbury to evaluate whether the amount of water being pumped at the site can be reduced while still keeping PFCs from moving away from the site.
For more information, please visit our websites:
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Site Related Links:
- Perfluorochemical Contamination in Southern Washington County, Northern Dakota County, and Southeastern Ramsey County, Minnesota, January 5, 2012 (PDF)
- The 3M Cottage Grove Facility and Perfluorochemicals
- VOCs: Volatile Organic Chemicals in Private Drinking Water Wells
- MDH Perfluorochemicals and Health webpage
- Minnesota Pollution Control Agency: Perfluorochemicals
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