WPSC Marinette MGP Site

May 2013

Ground water and upland soil sampling resumed in April at the location of the former MGP site (including the wastewater treatment plant and Boom Landing Park).  Contractors have been collecting ground water samples from the existing monitoring well network by opening up the wells and drawing samples using a mechanized water pump.  Contractors may also be seen in the area collecting soil gas samples.  This involves drilling quarter-sized holes up to 2 feet into the ground and inserting thin plastic hoses to collect samples over a 24-hour period.  Ground water sampling is expected to run quarterly through December 2014. 

Additional soil gas sampling may be necessary after the first round of results is processed by August. When all of the soil and ground water sampling results come back from the lab, they will be used to help complete the remedial investigation report by July 2014. This report will identify how much PAH contamination there is and where it is located.  Another document, called the feasibility study, will follow in 2015. It will list several possible ways to clean up the site.

An expedited cleanup of PAH-contaminated sediment in the Menominee River was completed in March. WPSC/Integrys funded and conducted the cleanup under EPA oversight.  It included:

• building a sheet pile “coffer dam” to isolate the areas from which contaminated sediment will be removed
• excavating contaminated sediment using a backhoe on the back of barge
• backfilling some of the excavated areas with clean sand and gravel setting up a monitoring program for the remaining PAHs that have been covered with a sand and gravel mixture
• treating excavated water on shore before it is released back into the river
• mixing dewatered sediment with a cement-like additive to solidify it for easier transportation and disposal
• transporting the mixture to an off-site licensed landfill for proper disposal

This is one of two major sediment removal projects on the Menominee River. Staff from a different EPA program is overseeing the Ansul Inc. project.  Everyone is working together to coordinate the cleanups. When these sediment removal projects are completed by 2014, EPA’s Great Lakes National Program Office can begin habitat restoration and consider deleting the Menominee River from its list of Areas of Concern, possibly in 2016.

Plans to investigate sediment, ground water and soil at six MGP sites began after a legal agreement called a consent order was signed between WPSC and EPA in May 2006. This agreement allowed for further investigation of the Marinette site and will determine how much contamination remains in soil, sediment and ground water.

The 2006 agreement also includes five other MGP sites in Green Bay, Manitowoc, Oshkosh, Two Rivers, and Stevens Point, Wisconsin. A separate agreement for another site, WPSC Campmarina in Sheboygan, was signed between WPSC and EPA in January 2007.