The settlement agreement required Water Gremlin to investigate for lead and other contaminants on its property. The first phase of this investigation was completed in August 2019; the second phase was completed in February 2020. The following results have emerged so far:
- Lead is present in soils and subsoils on the property. VOCs are also present in soil on the property.
- Lead was also found in surface water and sediments in the ditch south of the main Water Gremlin building and in stormwater ponds on the property.
- VOC vapors, including tDCE and trichloroethylene (TCE), were found under the building’s slab
- Shallow groundwater on the property is contaminated with VOCs and 1,4-dioxane (but it is not used for drinking water).
- 1,4-dioxane was found at low levels (significantly below the health-based drinking water guidance levels) in several private drinking water wells in the area.
Contamination in the vapor under the Water Gremlin building was high enough to trigger MPCA requirements for expedited action, and Water Gremlin has installed a vapor mitigation system in the building. The investigation will continue with further sampling of soils, soil vapor, groundwater, surface water and sediment, extending as far past the building's footprint as necessary to define the extent and magnitude of the contamination. Water Gremlin will be required to respond to any contamination that is above MPCA action levels and determined to pose a risk to human health and the environment.
Phases 1 and 2
The maps below show what was found in the first two phases of the investigation. Further updates will be posted here as the investigation proceeds.
TCE in groundwater
TCE is no longer used at the facility but is present in shallow groundwater (which is not used for drinking) on the site. The Minnesota Department of Health conducted sampling in the spring of 2019 and found no contamination in private drinking water wells. Additional sampling is being conducted to determine the extent and magnitude of this contamination.
1,4-dioxane in groundwater
1,4-dioxane is used as a stabilizer for chlorinated solvents such as trichloroethane and TCE. While these solvents are no longer used at the facility, 1,4-dioxane is present in shallow groundwater (which is not used for drinking) on the site. MDH collected water samples from private wells in late January and early February, 2020. Three of the eleven wells samples had detectable levels of 1,4-dioxane. The concentrations found were between 0.06 and 0.12 parts per billion (ppb), significantly less than the 1 ppb health-based drinking water guidance value. Sampling of additional private wells in the area occurred in late July 2020. Additional sampling is being conducted to determine the extent and magnitude of this contamination.
Lead in soils
Lead was previously investigated on the site in the 1990s and 2000s and a small area of lead-contaminated soil was excavated and removed. Recent sampling found some areas that exceed the current screening values below the building footprint or directly southeast of the building.
Lead in surface water and sediments
Testing showed the presence of lead in surface water and sediments on the Water Gremlin property and in the nearby creek. Additional testing of surface water and sediments for lead is being conducted in the stormwater ponds on Water Gremlin property and downstream of the property.
TCE in soil vapors under the building
Water Gremlin installed a vapor mitigation system under the building. The vapor that is being drawn up through the mitigation system is filtered twice to capture VOCs such as tDCE and TCE, and samples collected from the stack verify the effectiveness of these carbon filtration systems. So far, stack monitoring has shown that this equipment has captured nearly 100% of the TCE and tDCE that is being drawn up through the mitigation system. Water Gremlin will be replacing the filters as needed to continue removing VOCs from the air discharge. Any discharge of VOCs from the mitigation system will be considered by the Industrial Division when reviewing the permit application.