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ARDEN HILLS CITY COUNCIL WORK SESSION — MAY 16, 2011 2 <br />as a superfund site because of the level of contamination. At that time, the U.S. Army took <br />responsibility for clean -up of Round Lake. The U.S. Environmental Protection Agency g y <br />regulates environmental mitigation at superfund sites. Round Lake has been closed to the public <br />and there has been an attempt to maintain a high water level due to the contaminants in the <br />sediment. <br />Mike Fix, U.S. Army, explained that the Army started investigating the TCAAP area in 1979. In <br />1981, it was discovered that New Brighton and St. Anthony drinking water being drawn from this <br />site was contaminated and immediate steps were taken to protect the residents of those cities. In a <br />1984 Risk Assessment, it was determined that there were unacceptable ecological risks at Round <br />Lake. The Army drafted a feasibility study to mitigate or correct those contamination problems. <br />Since there was no immediate health risks, very limited activity took place at Round Lake from <br />1984 to 2010. After the last draft of this study in April 2010. regulators determined that <br />additional investigation was required. This investigation was completed in January and February <br />2011. The results of that investigation have just been compiled and distributed to regulators, but <br />regulators have not yet had a chance to review that data. There were 135 oints of investigation <br />p g <br />for 7 contaminants. At this time, Mr. Fix explained, they don't know what the remediation <br />recommendation will be or how much or what needs to be cleaned up. The regulators will be <br />meeting June 1 to review the data. Another draft of the feasibility study will be required by <br />regulators by this fall at the earliest. He also explained that public involvement will take place at <br />some point in the process. He added that the EPA makes the final determination of what needs to <br />be done. <br />Deepa DeAlwis, Minnesota Pollution Control Agency (MPCA). explained that protecting human <br />health is the primary concern for the MPCA and the EPA. She explained that an enormous <br />amount of soil clean -up and water clean -up has been done to address the immediate threat to <br />human health. Now, she explained, they are considering the ecological risks. She added that the <br />MPCA is receptive to hearing residents' concerns. <br />Councilmember Holden commented that the residents would prefer Round Lake remain a lake <br />rather than become a wetland area. She then asked what the feasibility study would include. <br />Mr. Fix stated that first they must determine what needs to be addressed and that could range <br />from recommending no further action to applying a cap to the bottom of the lake, or dredging the <br />lake bottom. <br />Mayor Grant asked for clarification of what capping the bottom of the lake would entail. <br />Mr. Fix explained that the cap could be a thin membrane to contain contaminants but that may <br />not satisfy U.S. Fish & Wildlife Services. He also stated there could be a thick ca p but that would <br />impact the aesthetics of the lake. Another option would be dredging the lake and back- filling with <br />clean sediment. He further explained that the feasibility study would include cost, and that there <br />are nine criteria that the alternatives are evaluated against. <br />Ms. DeAlwis explained that when the MPCA reviewed the previous feasibility study's limited <br />data set, they did not feel they had enough information about the sediment. The most recent <br />