July 11, 2013 Special Meeting

Special Council Meeting with representatives of the MN Department of Health (“MDH”) and MN Pollution Control Agency (“MPCA”) – MPCA Update on Minnetonka Lakeshore Advance Machine Site Power Point Presentation.


Attendance:  Reinhardt, Williamson, Hughes, Bren.  Sippel excused. Administrator Tolsma, City Clerk Lewin, Utility Superintendent Goman, Attorney Beck.


Guests:  Doug Beckwith, MPCA; Rick Jolly, Hydro geologist, MPCA; Ike Bradlich MDH; Jim Kelley, MDH; Ginny Yingling MDH; Steven Kelly and Aaron Baker both with Nilfisk Advance Machine.


Rick Jolly said this is about the previous Advance Machine site located at West Arm Drive.  He said initially the site was developed by Streater Industries and they manufactured wood products.  Advance Machine, manufacturers of large industrial floor cleaning equipment, operated on the site between 1958-1987. The site was then sold for redevelopment. He said during demo of the Advance Machine facility there were underground storage tanks removed. Jolly said a soil and ground water investigation was conducted and trichloroethylene (“TCE”) was discovered.  A search for responsible parties was launched and Nilfisk Advance Machine was identified. Nilfisk joined the MPCA Voluntary Cleanup Program.  Contaminated soil was removed from the site during construction of West Arm Townhomes.  Groundwater monitoring wells were installed and a water treatment plant was constructed. Jolly said because the city is on a municipal water supply the clean up goal was based on surface water standards.  He said the pump and treat system installed in 2003 is deemed to be an adequate system.  Clean treated water is discharged from the treatment plant into the lake during non-winter months.  Reinhardt wondered if the discharge could run all year round versus in just non- winter months, and it would be a possibility if dangers of thin ice could be dealt with.


Jolly said, in the future there will need to be additional access to properties at West Arm Townhomes for monitoring purposes.  Jolly shows a slide illustrating the groundwater concentrations.  He said there is some long-term leaching.  He said there has been over 1200 lbs of TCE removed since April, 2004.  Jolly said this is going to be a long-term pumping effort.  Hughes wonders what is meant by long-term and Jolly said at least ten more years.


Jolly also discussed the issue of vapor intrusion at the townhomes.  He explained vapor intrusion is simply migration of contaminant vapors from sources (water and soils) upwards through soil space. He said it is the same as Radon except Radon is naturally occurring from minerals.  He said a vapor intrusion investigation was launched in 2006 and initially eleven townhomes were sampled for soil gas concentrations.  One was found to be above the indoor screening value.  A sampling plan was developed for evaluation and mitigation has been offered to all the townhomes.  To date, 13 townhomes have accepted the mitigation system, some have said no and some have not responded.  MPCA will follow up with townhome residents in the future.  Williamson asked about homes to the west of the townhome complex.  Jolly said there will be testing to see how far this extends. 


Jim Kelly discussed the standards for TCE levels in groundwater.  He said that previously the state recommendations coincided with the federal drinking water standard.  MDH has recently issued a new guidance value for TCE’s based on the completion of a 10 year study of health effects of TCEs.  The purpose of the guidance value is risk assessment, not enforcement. He said the study is a thorough document about the toxicity of TCE and the report found there are additional health effects including immune system effects.  Kelly said the risk remains low, however.  Reinhardt asked if the guidance value will become a rule and Kelly said it might not be until 2015; however, the state guidance value applies only to private wells, the federal drinking water standard applies to community water supply systems.  He said that the state TCE groundwater guidance values are threshold values and TCE levels above the values are still low risk.  


Ike Bradlich referred to a fact sheet that sums up everything discussed so far.  He works with standards and violations and compliance.  He does compliance monitoring and collects samples.  Hughes asked where the samples were taken from - which well.  Goman said it can be determined by dates.  Williamson asked about the correlation with the date of rehabilitating the wells and the possibility of contaminants being disturbed during that process. He said it's quite coincidental that the dates are close.  Bradlich doesn’t believe well rehab work affected the test results.  He said right now, based on the findings, sampling can go back to annual monitoring instead of quarterly monitoring.  Reinhardt said the city also tested each of the city wells and the results differed from the MDH results, well two in particular was significantly lower.  Bradlich said he didn’t know why the test results were different.  It was determined the range of accuracy of the MDH test is 30% plus or negative. 


Ginny Yingling spoke about Spring Park’s aquifers.  She said there is no evidence of faults in the bedrock.  She said if they do exist it may disrupt the shale layers and they might not be as competent as they should be.  She said the contamination may be following the underground sand valleys.  She said there is currently no direct evidence that links the source of TCEs from the Advance Machine site to the city wells. 


Williamson asked about past practices with dumping of hazardous waste and its infiltration.  Jim Kelly said there are contractors that are hired to do evaluations and address past practices with hazardous waste.  Reinhardt asked about the probability that a source can be determined and the reliability of any determination. She wonders how much is science and how much is guessing.  Beckwirth said it can be a dance.  He said sometimes they don’t find any obvious source.  He said there is no one clear way of doing things.  He said there are adjustments that need to be made along the way.  Reinhardt asked how long this investigation to find the source would take.  Jolly said a Phase 1 paper investigation takes about three months.  He said they can try to collect information on their own to confirm or refute findings.  Well surveys can be conducted to find preexisting wells and what happened to them, whether they’ve been properly sealed or not.  Reinhardt asked about the city’s responsibility to inform residents.  Kelly said they will assist the city in informing the residents.  It could be a newsletter article, it could be open house meetings.  Williamson said accuracy is important and a statement about it’s an area of concern.  He’s concerned about prematurity of notification until they know what the next step is.  He asked the speakers for a timeline. Beck said there’s been a lot of information presented and it needs to be absorbed. She suggested the council can begin a plan of next steps at the next work session. 


Adjourn at 9:20 p.m.