Minnesota's environmental officials are proposing an update to the state's list of Superfund sites by removing one Minneapolis site from the Permanent List of Priorities (PLP) and adding nine new ones.
There are currently 74 abandoned hazardous waste sites listed on the PLP, also known as the State Superfund List, which is managed by the Minnesota Pollution Control Agency and the Minnesota Department of Agriculture; however, if the current proposed update is adopted, that number will jump to 82.
What is a Superfund?
Superfund is a name given to an environmental program designed to address hazardous pollution. The federal Superfund Program was established by the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) of 1980, which followed the discovery of toxic waste dumps at Love Canal and Times Beach in the 1970s.
Minnesota passed its Superfund law, the Minnesota Environmental Response and Liability Act (MERLA) in 1983 to address contaminated sites in the state. MERLA contains cleanup requirements and legal obligations that are consistent with the federal legislation. If accepted, each of the proposed sites now under consideration would be eligible for state-funded cleanup actions by the MPCA or MDA.
Superfund cleanup processes tend to be long, complex and geared toward remedying pollution and removing health hazards as needed in a specific area. A Superfund declaration generally allows officials to:
- Conduct removal actions
- Enforce penalties against responsible parties
- Engage the community
- Design long-term strategies
Minneapolis impound lot cleanup 'complete'
Although the impound lot in Minneapolis isn't a place most residents are eager to visit anyway, it has been a designated Superfund site since the late 1980s. Known as the Basset Creek/Irving Avenue dump site, the 35 acres located just west of downtown were once a dump prior to the 1960s. Today, much of the site is covered in asphalt.
In conjunction with the MPCA, the Minneapolis Public Works Department conducted remediation efforts after the site was declared a Superfund in 1986 because the soil contained lead, polynuclear aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs) and other contaminants.
In mid-October, a summarized investigation concluded that cleanup work was completed and no further action will be necessary -- unless the city intends to use the property in a way that might disturb the soil, that is. Since Minneapolis city officials intend to retain ownership and continue using the area as an impound lot, officials are ready to remove it from the Permanent List of Priorities.
Nine new Superfund sites?
The MPCA and the MDA now have several other locations across the state on their shortlist for Superfund consideration. A short summary of the location and the environmental concerns of each can be found below. Three are within the Twin Cities metro.
Precision Plating was once located at 230 Girard Avenue, but plating operations stopped at 2003. The building was sold a year later; however, the soil on site is still contaminated with chemicals used in the plating process, including:
- Trichloroethylene (TCE)
- Vinyl chloride
Groundwater in the area is also contaminated by metals and cyanide, and both have been detected across much of the site in concentrations that exceed the state's limits for health risks.
Currently, the site is a mixed commercial and residential area, and officials' primary concern is that the groundwater in the shallow aquifer may degrade and could even discharge into Basset Creek, a tributary of the Mississippi River. Additionally, officials say chlorinated VOC solvent vapor intrusion is a risk to buildings on the property and nearby. Officials are urging further investigation into the size of the plume.
The source of the groundwater contamination remains unknown, but when MDH officials sampled residential wells during a statewide effort to examine dump sites, VOCs were located.
Although the concentrations were considered low, the following contaminates have prompted concern:
- Trichloroethylene (TCE)
Drinking water advisories were issued at homes where the concentrations exceeded Minnesota Department of Health guidelines. In fact, the MPCA declared an emergency and used state Superfund money to supply bottled water to affected residents.
A new municipal water supply system was put in place in the early 1990s, and all wells were sealed as homeowners affected by the advisories were connected to the new system. Sampling later that decade found no increase in the wells, and the plume appeared stable. By 2000, the site was removed from the list.
Last May, however, MDH testing conducted TCE testing and found several wells now exceed the recommended levels. In response, the MPCA wants to put the site back on the list in order to further investigate the water contamination, monitor current residences and ensure citizens have a safe drinking supply available for the long-term.
A 17-acre site located about 4 miles south of Dundas, Minn., that was originally a gravel pit has been recommended due to unrestricted waste disposal that took place between 1964 and the mid-1970s.
Officials say waste materials were placed in and around the pit, and even burned occasionally. The MPCA installed groundwater monitoring wells since many residents nearby rely on wells. Since it is a rural area, there is no municipal water supply -- and it's not likely one would be constructed soon.
At least one residential well in the area contains vinyl chloride beyond safe levels. A GAC filtration device was installed in 2001 to make the water safe to drink, but the MPCA wants to add the site to the list so they can continue to monitor and treat additional wells while conducting a larger investigation of the contaminant plume.
Located at 612 11th Avenue Northwest, a single building occupies the commercial area affected. The western third of the building where the clothing care business was located was heavily damaged by fire in 2000.
Since then, environmental investigations found perchloroethylene (PCE) and trichloroethylene (TCE) in the groundwater at the site. Officials say there are potential human health risks associated with vapor intrusion, and the contaminants could even impact underground utilities, Cascade Creek and an industrial water supply well.
The 1.5-acre site located at 315 Hennepin Avenue South is in a mixed industrial and residential area that is just about a quarter mile from Mille Lacs Lake. In the 1950s, a metal plating facility occupied the area and discharged both toluene and trichloroethylene (TCE) to the sewer before 1978.
The facility was destroyed by fire in 2008, but tests conducted beforehand found the soil was contaminated with chlorinated VOCs, which were also in the groundwater at concentrations that were above state health limits. Additionally, runoff from firefighting carried some of the acids, bases, cyanide and other heavy metals used in plating into nearby low-lying areas. Elevated mercury and nickel levels have been found in surface soils, and vapor samples also show elevated levels of VOCs that could enter nearby homes and may require corrective actions.
An emergency partial clean-up of the half-acre, tax-forfeited property located at 300 West 14th Street was conducted by the MPCA in 2007, and indoor air levels were deemed acceptable despite mercury contamination seen there.Yet, even though the partial clean-up did include removal of debris and contaminated surface soils, soil analyses from 2013 found mercury in near-surface soils once more.
The site is located in a residential neighborhood, and officials say their main concern is that citizens could be at risk if they come in direct contact with contaminated soil through digging or other excavation. The MPCA says funds are needed to respond and protect human health.
The 2.75-acre site at 1504 Fourth Street South once housed a snow rake manufacturer, a lumberyard, a hardware store and a rental business that supplied tools and equipment. An environmental investigation began in 1990 after heating oil was released from an underground storage tank. In 2004, dioxins and the wood-treating chemical pentachlorophenol (PCP) were found, and groundwater monitoring has shown a low-risk but stable groundwater plume. Meanwhile, the dioxins and PCP in the soil do pose a direct-exposure risk and must be removed and disposed of off-site.
As the state's leading regulatory authority for agricultural chemicals, the Minnesota Department of Agriculture is recommending the Beltrami County site due to pentachlorophenol (PCP) contamination. Officials say PCP was used to treat wooden poles from 1971 to 1980. In 1997 and 1999, the U.S. Environmental Protection Agency completed emergency removal actions, including soil excavations and removal of tanks and sludge. Even so, MDA investigations indicate that there is still significant PCP contamination in the groundwater -- and that it is migrating off site. In fact, it could pose a threat to a food production well.
Officials believe corrective actions -- ranging from groundwater remediation and possible soil correction -- are needed to address the contaminants. In the absence of a viable responsible party, the MDA would require state funding to complete the clean-up.
As it is surrounded by mostly seasonal residences with private wells, officials are concerned about elevated levels of tetrachloroethene (PCE) and trichloroethylene (TCE) on the south side of Shagawa Lake west of Ely. In 2002, the contamination source was traced to a ditch where chemicals had been dumped. Since 2003, the MPCA has treated water at three nearby wells using granulated activated carbon to make it safe to drink. Two of the wells had levels of PCE and TCE that were above health standards.
Officials plan to add the site to the Superfund list to continue monitoring and treating drinking water in the area as well as investigate whether vapor intrusion has occurred at residences nearby.