A History of Twin Cities Drinking Water Contamination

Has your home or neighborhood been affected by drinking water contamination? The answer might surprise you.

Minnesota is known for its 10,000 lakes and natural beauty. But water quality has taken a few hits over the years. Some water impurities like Arsenic can come from natural sources. Others come from chemical spills and dumping.

This article outlines some of the larger sources of drinking water contamination that have been reported over the years.

1: Edina Plume

Location: Edina, Hopkins, St. Louis Park
Year pollution discovered: 2002
Main chemicals: Vinyl chloride
Plume size: 5,682 acres/ 8.9 square miles
Aquifer mapped: Prairie du Chien-Jordan

Edina shut down a city well in 2003 after Vinyl chloride was detected. Investigators have discovered a large plume of low-level contamination, yet the source remains unknown. This plume intersects with another chemical plume from the former Reilly Tar & Chemical site in St. Louis Park (See No. 2). That site has been ruled out as the source of the Edina plume. Experts think that the pollution may have come from several industrial sources, and the plume’s movement may be affected by the many powerful wells drawing on the aquifer.

Vinyl Chloride

Vinyl chloride is a colorless gas with a mild, sweet odor. It does not occur naturally, but can be formed when other substances break down in disposal sites. As a manufactured chemical, it is used to make polyVinyl chloride (PVC).

2: Reilly Tar & Chemical Plume

Location: St. Louis Park, Hopkins
Year pollution discovered: 1932
Main chemicals: PAHs
Plume size: 2,276 acres/ 3.6 square miles
Aquifer mapped: Prairie du Chien-Jordan

The groundwater contamination beneath St. Louis Park was discovered in 1932, when the city drilled a well and struck creosote-laden water. The pollution is from the former Reilly Tar & Chemical Corp.

Today, it takes constant pumping by several special wells to prevent this plume of pollution from moving, and the creosote tar could remain a threat into the next century.

Polycyclic aromatic hydrocarbons (PAH)

A group of over 100 different chemicals formed during the incomplete burning of coal, oil and/or other organic substances. Manufactured PAHs usually are colorless, white or pale yellow-green solids. They are commonly found in coal tar, crude oil, creosote and roofing tar.

3: South Minneapolis Arsenic Site

Location: Minneapolis
Year pollution discovered: 1995
Main chemicals: Arsenic
Plume size: 23 acres/ 0.0 square miles
Aquifer mapped: Water table

Former pesticide operations (1938-1968) left arsenic in the groundwater beneath 23 acres. Soil contamination spread over an even broader area. This Superfund site has focused mostly on neighbors’ yards contaminated by wind-blown dust. However, a substantial arsenic plume also exists in the groundwater.

Arsenic

This semi-metal element is odorless and tasteless. It enters water from natural deposits in the earth or from agricultural and industrial practices.

4: Shoreham Yard — West Plume

Location: Minneapolis
Year pollution discovered: 1987
Main chemicals: PCP
Plume size: 411 acres/ 0.6 square miles
Aquifer mapped: Prairie du Chien-Jordan

From 1915-1972 a railroad-tie treatment operation in the Soo Line rail yard contaminated groundwater. This 100+ block plume of PCP, a wood-treating chemical, lies beneath northeast Minneapolis in the area known as Cedar Service. PCP was confirmed in 1989 by a state investigation, and cleanup began in 1997. Another effort at soil cleanup using PCP-eating bacteria now is underway. Groundwater issues off site still are being studied.

Pentachlorophenol (PCP)

An organic solid with needle-like crystals and a phenolic odor. Used as a wood preservative (fungicide), and once widely used as an herbicide. Banned in 1987 for these and other uses, as well as for any over-the-counter sales.

5: Shoreham Yard — East Plume

Location: Minneapolis
Year pollution discovered: 1994
Main chemicals: VOCs (PCE, DCE, TCE, Vinyl chloride)
Plume size: 360 acres/ 0.6 square miles
Aquifer mapped: Glacial Outwash-St. Peter Sandstone and Prairie du Chien-Jordan (offsite plume)

A historic railroad roundhouse and separate chemical distribution center on the east side of the Shoreham Yard are the source of one of two plumes of groundwater contamination that extend south of the yard. This plume contains a degreasing chemical and other solvents. On-site cleanup of soil is underway, while groundwater off site still is being studied.

Volatile organic compounds (VOCs)

A variety of chemicals used and produced in the making of paints, pharmaceuticals and refrigerants. Many are industrial solvents, such as trichloroethylene, and they are a common groundwater pollutant.

6: Fridley Ordnance Plant Plumes

Location: Fridley
Year pollution discovered: 1981
Main chemicals: TCE
Plume size: 69 acres/ 0.1 square miles
Aquifer mapped: Shallow drift

Solvents were dumped at the Naval Industrial Reserve Ordnance Plant plant in Fridley from the 1940s-1960s. The TCE plume extends beneath the nearby Anoka County Riverfront Park.

In 1981, state environmental officials discovered the degreaser TCE in on-site wells, and one sample showed barely detectable levels of TCE in the Minneapolis water supply intake. The U.S. Navy removed contaminated soil and drums, stopped using TCE and installed a system to pump out groundwater and treat it. A military contractor that formerly operated on the site dug up other contaminated soil, and installed a second groundwater pump-out system. These systems have operated for about two decades.

Federal officials once worried that two pollution plumes were too close to the Minneapolis city water supply intake on the Mississippi River. It appears the plumes no longer threaten the Minneapolis water supply.

Trichloroethylene (TCE)

Colorless or blue organic liquid with a chloroform-like odor. Used to remove grease from fabricated metal parts and some textiles

7: Blaine Plume

Location: Blaine
Year pollution discovered: 1993
Main chemicals: 1,2-Dichloroethane (DCA)
Plume size: 1,082 acres/ 1.7 square miles
Aquifer mapped: Jordan and St. Lawrence Aquifer

In 1993 the industrial chemical DCA was found in 3 wells, and affects groundwater beneath 1-square miles.

The source of this broad area of groundwater pollution in Blaine has eluded investigators for more than a decade. After discovering the industrial chemical in the wells, Blaine officials stopped using two of them. The third well had low levels of the chemical, which was diluted further in the water supply. In October 2006, the city opened a new treatment plant that removes the chemical, allowing the two most-affected wells to be used again.

1,2-Dichloroethane (1,2-DCA)

Colorless, oily organic liquid with a sweet, chloroform-like odor. Used in chemicals for plastics, rubber and synthetic textile fibers, as a solvent for resins and fats, photography, photocopying, cosmetics and drugs, and as a fumigant for grains and orchards.

8: East Bethel Landfill plume

Location: East Bethel
Year pollution discovered: 1982
Main chemicals: VOCs(DCA, methylene chloride, TCE), benzene*
Plume size: 117 acres/ 0.2 square miles
Aquifer mapped: Water table, intermediate and deep drift aquifer

Groundwater was contaminated at a closed demolition landfill that once accepted industrial waste. Seven wells extract water, which is treated and released into Ned’s Lake. The covered landfill has been reseeded with native plants and is part of the Sandhill Crane Natural Area. Nearby private wells have not been affected, though officials monitor them once a year.

Volatile organic compounds (VOCs)

A variety of chemicals used and produced in the making of paints, pharmaceuticals and refrigerants. Many are industrial solvents, such as trichloroethylene, and they are a common groundwater pollutant.

9: Army Ammunition Plant Plume

Location: Arden Hills, New Brighton, Columbia Heights, Fridley, Mounds View, St. Anthony, Minneapolis
Year pollution discovered: 1981
Main chemicals: TCE, other VOCs
Plume size: 4,952 acres/ 7.7 square miles
Aquifer mapped: Prairie du Chien

A large plume of polluted groundwater emanates from a World War II-era ammunition plant that operated in Arden Hills from 1941-1975. Industrial chemicals, mainly TCE, were burned and dumped into the ground. They spread widely in groundwater, affecting two suburbs’ water supplies. Activated carbon filters cleanse the municipal water in New Brighton and St. Anthony. The constant pumping in New Brighton since 1990 has halted the plume’s expansion. The pumping likely will be needed for 20 to 40 years. Other work included removing contaminated soil and buildings.

Trichloroethylene (TCE)

Colorless or blue organic liquid with a chloroform-like odor. Used to remove grease from fabricated metal parts and some textiles

10: Wood Treatment Plume

Location: New Brighton
Year pollution discovered: 1979
Main chemicals: PCP, arsenic, chromium, dioxin
Plume size: 149 acres/ 0.2 square miles
Aquifer mapped: Shallow drift

Shallow groundwater near the closed MacGillis & Gibbs plant is extracted and treated to remove wood-preserving chemicals. This site of a wood treatment plant is largely cleaned up and redeveloped, but an off-site groundwater contamination plume remains. The soil and groundwater were contaminated with wood preservative. A groundwater treatment system has reduced PCP levels and prevented additional pollution from migrating off site, according to a 2006 state analysis.

Pentachlorophenol (PCP)

Uses: An organic solid with needle-like crystals and a phenolic odor. Used as a wood preservative (fungicide), and once widely used as a herbicide. Banned in 1987 for these and other uses, as well as for any over-the-counter sales.

11: Hwy. 96/North Oaks Plume

Location: North Oaks, White Bear Township
Year pollution discovered: 1986
Main chemicals: Vinyl chloride
Plume size: Unknown
Aquifer mapped: Prairie du Chien

Contamination from a dump on Hwy. 96 (1920s-1974) has migrated under Gilfillan Lake in North Oaks, affecting some residents’ wells. The groundwater plume in North Oaks is blamed on a former trash and chemical dump in neighboring White Bear Township after a U.S. Environmental Protection Agency investigation discovered volatile organic compounds (VOCs) beneath the Hwy. 96 dump in 1986. Chemicals first turned up in private wells on the east shore of Gilfillan Lake in North Oaks in the early 1990s. In 2004-2005, three homeowner wells on the west side of the lake tested positive for Vinyl chloride, a cancer-causing breakdown product of VOCs.

Vinyl chloride

Vinyl chloride is a colorless gas with a mild, sweet odor. It does not occur naturally, but can be formed when other substances break down in disposal sites. As a manufactured chemical, it is used to make polyVinyl chloride (PVC).

12: Baytown Township TCE Plume

Location: Baytown and West Lakeland townships, Lake Elmo, Bayport
Year pollution discovered: 1987
Main chemicals: TCE
Plume size: 7027 acres/ 7.2 square miles
Aquifer mapped: Prairie du Chien and superficial aquifers

The degreasing chemical TCE turned up in private wells in Baytown Township 30 years ago. Experts believe the contamination came from a long-closed equipment manufacturer (1940-1968) in Lake Elmo. A groundwater extraction system is now planned there to contain the plume. The pollution affects groundwater across a 7-square-mile area. 160 private wells in Baytown Township and West Lakeland Township, and 1 in 3 Bayport municipal wells now require treatment to rid the water of the chemical. About 100 other wells in the plume area contain TCE at levels below the federal drinking water standard of 5 parts per billion.

Trichloroethylene (TCE)

Colorless or blue organic liquid with a chloroform-like odor. Used to remove grease from fabricated metal parts and some textiles.

13: Lakeland Plumes

Location: Lakeland, Lakeland Shores, Afton
Year pollution discovered: 1978
Main chemicals: VOCs, BTEX
Plume size: 1,783 acres/ 2.8 square miles
Aquifer mapped: Not available. Groundwater chemical concentrations have not been fully mapped by state officials.

Chemicals in about 100 private wells prompted construction of a municipal water supply in 1991. State testing of private wells in Lakeland in the 1980s revealed widespread groundwater contamination from petroleum-related chemicals and solvents, all heading toward the St. Croix River. At least 2 plumes of groundwater pollution exist. One is from a former truck stop; the source of the other has not been confirmed. High nitrates from septic systems and other sources are another problem with the area’s groundwater. The exact boundaries of the chemical pollution plume have never been established by regulators.

Volatile Organic Compounds (VOCs)

A variety of chemicals used and produced in the making of paints, pharmaceuticals and refrigerants. Many are industrial solvents, such as trichloroethylene, and they are a common groundwater pollutant.

Nitrates

Nitrates can cause blood-oxygen deprivation in children, a condition known as blue-baby syndrome.

14: 3M Oakdale Dump Plume

Location: Oakdale, nearby areas
Year pollution discovered: 1980
Main chemicals: PFBA, other PFCs, VOCs
Plume size: 65,326* acres/ 102.1* square miles
Aquifer mapped: Jordan

A waste dump used from 1956-1960 by 3M for chemicals used in protective coatings like Scotchgard. 3M installed 12 wells in 1985 to extract groundwater and create a hydraulic barrier to prevent pollutants from flowing off site. State regulators believed the cleanup effort was working, because the area of solvent-tainted groundwater near the dump was shrinking. When the Health Department tested for PFCs in 2004-2005 they found elevated levels of PFCs in city and private wells in Oakdale and Lake Elmo. Later, a large PFBA plume was identified. The most recent plume maps show PFBA extending south toward Woodbury, intersecting with another plume from 3M’s Woodbury dump site.

The intersecting plumes from the two 3M dumps and the Washington County landfill cover 99 square miles in Washington County.

More than 170 private wells near the Oakdale dump and Washington County landfill had elevated chemical levels. 3M paid for a water-supply filtration plant in Oakdale and the extension of municipal water lines to affected residences in Lake Elmo. An environmental engineering consultant is investigating further cleanup options.

Chemical information: PFB

PFBA was used as a coating for photographic film. It is one of a group of 3M chemicals known as perfluorochemicals. Others in this class include PFOA, used in coatings such as Teflon, and PFOS, once used in stain-resistant products like Scotchgard. 3M stopped using them in 2002.

15: County Landfill Plume

Location: Lake Elmo and nearby areas
Year pollution discovered: 1983
Main chemicals: PFBA, VOCs
Plume size: 65,326* acres/ 102.1* square miles
Aquifer mapped: Jordan

Washington and Ramsey counties used this 40-acre former quarry in Lake Elmo as a landfill (1969-1975) for residential and industrial waste, including sludge from 3M.

Six years after it closed, organic compounds including benzene and vinyl chloride were detected in private wells. In the mid-1980s, about 100 residents’ wells were contaminated with VOCs, so their homes were connected to Oakdale’s water system.

Since then, water has been continuously pumped out of nearby wells and treated to reduce groundwater pollution and curb its movement. The 3M chemical PFBA was discovered in 13 private wells east of the landfill during 2006-2007. An artificially high water table caused by the landfill’s water treatment system is believed responsible for contamination of those wells, which are uphill from the landfill.

PFBA

PFBA was used as a coating for photographic film. It is one of a group of 3M chemicals known as perfluorochemicals. Others in this class include PFOA, used in coatings such as Teflon, and PFOS, once used in stain-resistant products like Scotchgard. 3M stopped using them in 2002.

16: 3M Woodbury Dump Plume

Location: Woodbury and nearby areas
Year pollution discovered: 1966
Main chemicals: PFBA, VOCs
Plume size: 65,326* acres/ 102.1* square miles
Aquifer mapped: Jordan

Former 3M dump (1960-1966) is one of three suspected sources of a large area of groundwater contamination. See also sites 14 and 15. 3M used this dump to dispose of industrial waste during the early 1960s. Isopropyl ether, an industrial solvent, was discovered in a shallow well on a nearby property in 1966.

Then, in 2004, 3M chemicals called PFCs were detected in the extraction wells. Later PFBA, a film coating chemical, was detected in nearby residential wells. A large plume of PFBA-contaminated groundwater has been identified south of the former dump. 3M’s manufacturing plant in Cottage Grove also lies within the plume of contaminated groundwater, but experts believe PFCs from the plant are going into the Mississippi River, not the groundwater to the north.

PFBA

Uses: PFBA was used as a coating for photographic film. It is one of a group of 3M chemicals known as perfluorochemicals. Others in this class include PFOA, used in coatings such as Teflon, and PFOS, once used in stain-resistant products like Scotchgard. 3M stopped using them in 2002.

17: Refinery/PCP Plume

Location: St. Paul Park
Year pollution discovered: 1985
Main chemicals: PCP, petroleum
Plume size: 14 acres/ 0.0 square miles
Aquifer mapped: Prairie du Chien aquifers

An oil refinery (now owned by Marathon Oil Co.), and a now-closed wood-treating business contaminated soil and groundwater with PCP, a wood preservative, and petroleum. Marathon is paying for cleanup, which requires constantly pumping out groundwater to prevent subsurface pollution from seeping into the Mississippi River.

Pentachlorophenol (PCP)

An organic solid with needle-like crystals and a phenolic odor. Used as a wood preservative (fungicide), and once widely used as an herbicide. Banned in 1987 for these and other uses, as well as for any over-the-counter sales.

18: Pine Bend Landfill

Location: Inver Grove Heights
Year pollution discovered: 1985
Main chemicals: TCE, TCA other VOCs
Plume size: 89 acres/ 0.1 square miles
Aquifer mapped: Drift aquifer

Small, stable plume in shallow groundwater near the Mississippi River. Groundwater is contaminated between this still-operating sanitary landfill and the Mississippi River (which is only 1 mile away). Allied Waste, which now owns the landfill, says a leachate collection system and an impervious cover on the landfill have improved the groundwater.

Volatile Organic Compounds (VOCs)

A variety of chemicals used and produced in the making of paints, pharmaceuticals and refrigerants. Many are industrial solvents, such as trichloroethylene, and they are a common groundwater pollutant.

19: Flint Hills Refinery Plume

Location: Rosemount
Year pollution discovered: 1997
Main chemicals: BTEX
Plume size: 263 acres/ 0.4 square miles
Aquifer mapped: Sand and gravel level and Prairie du Chien

Petroleum products are in the groundwater from the former Koch refinery to a trench at Spring Lake, a backwater on the Mississippi River 6 miles north of Hastings. Since 1998, when the refinery paid a record $6.9 million fine for water and air pollution violations, the company says it has spent another $30 million dealing with the problems, including pumping out 4.1 million gallons of petroleum products. That’s the equivalent of 500 tanker truckloads. The company also says it has fixed leaky tanks that contributed to the problem, and is committed to cleaning up the old pollution.

Benzene, Toluene, Ethylbenzene and Xylene (BTEX)

This group of volatile organic compounds (VOCs) is found in petroleum hydrocarbons, such as gasoline, and other common environmental contaminants.

20: Farmington Plume

Location: Farmington
Year pollution discovered: 1999
Main chemicals: PCE, TCE, 1,1,1-TCA
Plume size: 87 acres/ 0.1 square miles
Aquifer mapped: Based on overall sampling data from various depths.

A narrow plume of groundwater tainted with dry-cleaner chemicals migrates toward the Vermillion River. The pollution source is believed to be a former dry cleaner. The site was added to the Minnesota Superfund list in 1999. Two homes have had filters installed on their wells, while other residents with contaminated wells now receive municipal water.

Tetrachloroethene (PCE)

Colorless organic liquid with a mild, chloroform-like odor. Also known as perchloroethylene. Used in the textile and tanning industries, and as a component of aerosol dry-cleaning products.

What Does This Mean for You?

It seems like almost every inch of the Twin Cities has been touched by a chemical dump or spill doesn’t it? This list of drinking water contamination sites was first published in 2007. Since then, private businesses and the State of Minnesota have gone to great lengths to correct these problems.

But it seems like most communities had been drinking and bathing in their water for 20+ years before the problems were discovered.

Premier Water Technologies offers a variety of water purification systems. We can help you add a layer of your protection from past OR future contamination. Give us a call at (952) 767-0230 or sign up for a free water test and estimate.