WPSC Manitowoc MGP Site

May 2013

Ground water and soil sampling as part of a study called the remedial investigation has been ongoing since September 2012.  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.  They may also have been seen in the area collecting soil gas samples.  This involved drilling quarter-sized holes up to 2 feet into the ground and inserting thin plastic hoses to collect samples over a 24-hour period.  In May, the soil gas located under the slabs of nearby buildings will be sampled to see if vapor intrusion is occurring. 

Intrusion occurs when vapors rise up through the ground.  In this case, ground water polluted with PAHs turns into a gas and looks for an easy escape route through building slabs, concrete floors, basements, and crawl spaces.  High levels of PAH gas may cause adverse health effects but are easily addressed with the installation of basketball-sized “mitigation systems.” 

WPSC, the company determined to be responsible for the contamination, surveyed the terrain and contours of the land under the Manitowoc River in December 2011.   A year later, contractors also took sediment samples to get a better idea of where PAH contamination is located.  Results from the 2011 survey and the 2012 sediment samples are being used to start developing a more detailed river sampling plan this September.  The initial results and newly collected information will be included in a remedial investigation report.  This report is expected to be completed in early 2015.  Another document, called the feasibility study, will follow.  It will list several possible ways to clean up the site.

WPSC/Intregrys is funding and conducting all of the work.

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 allows for further investigation to determine how much contamination remains at the Manitowoc site.

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