Legislators updated on groundwater
A group of local state legislators met in Woodbury Aug. 14 to get the latest from the state department of health and Minnesota Pollution Control Agency on groundwater contamination issues involving perfluorochemicals (PFCs) found in several communities in Washington County.
Health department officials shared results from a point-of-use water filter study commissioned by the Legislature earlier this year with members of the East Metro PFC Oversight group.
MPCA officials also updated the group on the latest news in its efforts with 3M to clean up four former disposal sites where the Maplewood-based company once dumped PFCs.
Cottage Grove site
3M has proposed to add more ground extraction wells and dredge contaminated sediment in the east cove of the disposal site, but the MPCA requested the company obtain some additional information about contamination of the east cove before making a decision. The MPCA expects to hold a public meeting on those results in November and a possible approval of the cleanup plan for the Cottage Grove site could come early next year.
Oakdale disposal site
MPCA official Kathy Sather said the agency is reviewing proposed action which includes institutional controls that will limit future activities at the site. The proposed remediation also includes a plan to enhance the groundwater improvement systems at the site and excavation of contaminated soil to be disposed of off site. Sather said that 3M has also responded to public concerns about air exposure during the proposed excavation process by proposing to install a soil vapor extraction system in the excavation area.
The proposed cleanup plan recommended by MPCA staff includes institutional controls, continued operation of ground water pump-out systems with treatment of PFC contaminated ground water prior to discharge and the excavation of contaminated soil with off-site disposal. The MPCA is likely to make a final decision on the cleanup of the Woodbury site by December.
Washington County Landfill
The MPCA held a series of public meetings earlier this year to discuss remediation methods, and in June made an official decision to excavate the contaminated soil and place it in a "triple liner" container at the same site. Further evaluation on the volume of the contaminated waste needs to be done before construction can begin in January, Sather said.
The MPCA also made a decision to contract with KSB in Rosemount to store the contaminated soil it excavates from the various disposal sites.
State Rep. Karla Bigham, DFL-Cottage Grove, expressed her concerns about the method of transporting the contaminated soil, but was assured by MPCA officials that the trucks used to transport the soil would be secure.
The Minnesota Department of Health officials at the Thursday meeting informed legislators that the department is continuing to monitor the 84 private wells in the county that initially received drinking water well advisories. According to the department it will rescind advisories for 49 of those wells in the near future due to the fact that the level of perfluorobutanoic acid (PFBA) measured in the wells is below the health based value that was established earlier this year.
Officials also said they have continued to measure the level of PFCs in the affected wells and have seen either a stable concentration or a downward trend, but will continue to monitor the wells for the foreseeable future.
Long can be reached at email@example.com