The Bulinski Point Superfund site is located on a peninsula on the south shore of Shagawa Lake west of Ely, Minnesota. It is surrounded by mostly seasonal residences with private wells. Approximately 25 residences are within a quarter-mile radius of the site.
Contamination from suspected chemical dumping has been identified in three residential wells used for drinking water.
What's the problem?
- A site investigation in 2002 detected tetrachloroethene (also known as PCE, or "perc," a solvent used in industrial processes, metal cleaning, dry cleaning, and textile processing) concentrations in groundwater that exceeded the Minnesota Department of Health's (MDH) Health-Based Value of 4 micrograms per liter, also stated as μg/L. The source of the contamination was traced to a ditch where it was believed that barrels containing PCE were dumped.
In early 2003, the MPCA installed pairs of granular activated carbon water filtration units at three Bulinski Point residences. Since that time, the MPCA has regularly collected water samples at the three properties. PCE concentrations have ranged from 0 to 125 μg/L, but PCE and other volatile organic compounds have never been detected in any of the carbon-filtered samples. This indicates that the water filtration systems are effectively removing the contaminants.
- Well water samples are also collected regularly from three other nearby residents that do not have filtration units. Contaminants have not been detected in these other residential wells.
Soil vapor intrusion investigations were conducted in three residences in the source area beginning in November 2013. The investigations looked at whether soil vapors from the contaminated groundwater could be impacting indoor air. The results of the investigations do not indicate a risk of vapor intrusion into the homes.
Current MPCA site activity
The water supply wells located at affected residences are sampled semi-annually, and the carbon filtration systems are maintained. In 2016, the MPCA worked with the City of Ely and Morse Township in evaluating a permanent drinking water solution for the affected residents. In March 2017 the MPCA completed the Water Supply Alternative Analysis which evaluated alternative water supply sources. Based on the evaluation, the MPCA has determined that continued filtration of the residential wells is the most feasible and lowest cost way to meet the objective of providing a whole-house potable water supply that does not exceed drinking water standards established by the MDH. This decision is documented in the Minnesota Decision Document dated December 13, 2018.
- Source area investigation (c-s3-24a)
- Residential Water/GAC system sampling & site data review (c-s3-24b)
- GAC system & soil vapor sampling review (c-s3-24c)
- Water supply alternatives analysis (c-s3-24d)
- Minnesota Decision Document (final), Bulinski Point (c-s3-24e)
Sondra Campbell, Hydrogeologist, 651-757-2840