The Sherburne County Board voted unanimously Tuesday to begin conducting routine sampling of residential wells near the Elk River Landfill The zoning department first recommended testing the wells during a county board workshop on Dec. 3, 2014 because of findings of a contamination plume that would eventually be described in a hydrogeologic evaluation report presented by the landfill to the county in late December. 

 

David Kastner, environmental specialist with the zoning department, said since the Dec. 3 workshop, a volatile organic compound called dichlorodifluoromethane was found in a residential well down-gradient from the ERL.

 

Dichlorodifluoromethane is a compound found in refrigerants, solvents and aerosol spray propellants.

 

The landfill notified the county after it was discovered. On Feb. 2, the zoning department also received the 2014 Fall Quarterly Report and the 2014 Annual Water Quality Monitoring Report from ERL that detailed the dichlorodifluoromethane presence.

 

That detection was confirmed at 2.2 micrograms per liter (µg/L), which was well below the health risk limit of 700 µg/L.

 

ERL offered the homeowner bottled water, which is required under the county’s Solid Waste Management Ordinance, but the homeowner declined. Instead, the homeowner accepted the landfill’s offer to install a whole home carbon water treatment system.

 

The county is requiring ERL to submit a work plan by March 1 to define the contamination plume extending from the landfill.

 

At the recommendation of the zoning department, the county board has agreed to have Leggette, Brashears and Graham, Inc. (LBG), a groundwater and environmental engineering firm, conduct residential well sampling on up to seven residential wells down-gradient from ERL once annually at a cost of $7,398.

 

The board also approved split-sampling of 13 monitoring wells down-gradient of the landfill by LBG for $8,528.

 

“The purpose of this is to report certain contaminants the landfill is reporting at or below state health risk limits and intervention limits,” said Kastner.

 

Split-sampling means LBG will be present when ERL’s sampling technician is present, providing two independent laboratories analyzing the groundwater from each well for a comparison.