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Home My WebLink About1998-09-02 PACKET 08.B.REQUEST OF CITY COUNCI� ACTIdN COUNCIL AGENDA MEETING ITE� DATE 9/02/98 PREPARED BY Administration Ryan Schroeder ORIGINATING DEPARTMENT STAFF AUTHOR �,t.<��..�.<��>.��,��..<�..,��.«��«��.«.<� COUNCIL ACTION REQUEST Review 3M Woodbury Mitigation Proposal BUDGET IMPLICATION $ $ BUDGETED AMOUNT ACTUAL AMOUNT FUNDING SOURCE SUPPORTING DOCUMENTS � MEMO/LETTER: ❑ RESO�UTION: ❑ ORDINANCE: ❑ ENGINEERING RECOMMENDATION: ❑ LEGAL RECOMMENDATION: � OTHER: Update ADMINISTRATORS COMMENTS ; � City Administrator Date * * * * * * 'k * * * * * * * * * * * * * * * * X"k * * * * * * * 9 k * * > * * * k * +F * * * * # COUNCIL ACTION TAKEN: ❑ APPROVED ❑ DENIED ❑ OTHER Memo to: Mayor and City Council From: Ryan R. Schroeder Subj.: 3M Woodbury Site Date: August 28, 1998 This item was originaily on the August 19 agenda but was delayed at the request of the Minnesota PCA. On February 4, 1998 CounciB received a site evaluation report from Conestoga- Rovers and Associates. The report is entitBed " Northeast Area Technology Evaluation Report II." You may wish to bring your copy of this report to the Council meeting for reference during the PCA presentation. The report proposes natural attenuation as the preferred contamination control measure for contaminates emanating from the 5-acre acid pit disposal area within the 720 acre 3M site. The 3M site is located east of CR 19 and west of Lamar. It straddles the Cottage Grove/Woodbury border just north of 70` Street. At your February meeting it was presented that the Minnesota PCA would be providing their findings and conclusions regarding the report at a public meeting projected to be held, at that time, in June, 1998. This meeting has been delayed for a number of reasons to this meeting of September 2, 1998. The PCA had committed that they would be publicizing this meeting by a mailer to identified interested parties and by a news release. Enclosed is the most recent PCA update, dated August 1998, on the 3M Woodbury site. The PCA intent is to inform Council and the community of their suggested direction regarding the site. The Cottage Grove Councii may offer recommendations regarding that direction. It is my understanding that the PCA may choose a remedy in opposition to Councii desires if they deem that remedy as most appropriate. The PCA is reportedly hopetul, however, that you will provide affirmation of their remedy, which appears to be use of natural attenuation. �� Minnesota Pollution Control Agency • i • i ' f • . ' Cleanup/August 1448 Metro District, Remediation Section, Voluntary Investigation and Cieanup Program This Minnesota Pollution Control Agency (MPCA) fact sheet provides an update on the investigation and cleanup status of the 3M Woodbury site, which is being cleane8 up voluntarily by Minnesota Mining and Manufacturing (3M) under the state's Votuntary Investigation and Geanup (VIC} Pragram. Site Description The 3M Woodbury site is located approximately six miles south of Interstate 94, along the east side of Woodbury Drive and straddling the WoodburylCottage Grove boundary. Tha approximately 720- aere site consists of primarily low rolling hills. The surrounding land is used mostly for agricuttural purposes, with some scattered areas of residentiai development. Hisfory of the Site From 1960 untii 1966, 3M disposed of solid wasYe and spenf industrial solvents and acids in trenches at the site. The waste came from 3M's Cottage Grove and St. Paul manufacmring facilities. Two azeas were used for this disposal: the 10-acre "main disposal area" and the 5-acre "northeast disposal area" (see map). 3M stopped waste disposal in 1966 when isopropyl ether, an lndustrial solvent, was discovered in a shailow residential well on neazby property. In response, 3M began a comprehensive residential well-moniforing program. The monitoring showecl Chat no other wells had been affected. Two other areas at the site were used until 1969 by V,'oodbury and Cottage Grove residents for dumping municipal wasta, Waste in these disposal areas consisted mostly of household, automotive, construetion and commercial debris. In an effort to remove Yhe chemical contamination source, 3M excavated their disposal trenches and burned the waste on site during January and February 1968. (This took place before hazardous waste disposal regulations existed.) Tests co�ducted by 3M showed that the majority of the solid waste and soivents ��ere destroyed in the burning process. Minneso;a Pallution Control Agency, 520 Lafayette Road North, St. Paul, Minnesota 55155•4194 (651) 296•6300, toll•free (800) 657•3864, TDD (651) 282•5332 This material can be matle availeble in altemative formats for peopie with disabllifies. � Printed on recvdad nanPr c„�r��.,,. �� ia��: �n .........,< «_._ ..-_ ----- _ _ _, _ , ,_ 3M Woodbury disposal areas � Mlnnesota Pollution Control Aqency ""' Metro DistncURemediation $ecUOnNoluntery C]e3�u /E�U uSt 199g Invest;gation and Clearup Program P B 3M installed four pump-out (or "barrier") walls becween 1967 and 1973 to prevent further m igration of the ground water contaminants. These wells have been pumping continually sinae then, with the extracted ground water carried via a pipeline to the 3M Cottage Grove plant for use as cooling water in manufacturing processes. 3M notified Che U.S. Environmenial Protection Agency of the site in 1981, as required by the 1980 federal Superfund law. In 1983 and i990, MPCA Superfund staff evaluated the site for possible inclusion on the state or federa( Superfund lists. Both times, staFf determined that the site did not merit listing because of the cleanup work completed and the ongoing ground water pump-out system. Wbat has 3D7 done recently at the site? 3YI voluntarily entered the MACA's Voluntary Investigation and Cieanup Program in Apri] 1992. (The VIC Program provides review and approvaf ofvoluntary site investigations and cfeanups outside of the enforcement-oriented Superfund program, although the same cleanup standards are applied.) At that time, 3M proposed to conduct additional studies of the barrier wells' adequacy, investigate the northeast disposal area, and re-grade the property. VIC staff could not approve the proposal due to a lack of information about the site. The MPCA requested that 3M prepare a site history report and conduct additional investigations of the contamSnation remaining at the site. 3M's site history report, completad in August 1992, provided a11 avaitable data about past site operations, investigations and remedial acYivities, including on-sita and off-site ground water manitorin�. The report indicated that afrer isopropyl ether was first detected in a residential we(I in May 19fi6, no other drinking water wells have shown contamination oxiginating from the site. With VIC staff approval, 3M completed additional investigations at the site during 1992 and 1993. These studies showed that relatively low levels of contamination remained in the main disposal area and muntcipal disposal areas, and that aggressive cleanup measures ware not necessary in these areas. The northeast disposal area, on the other hand, was found to have significant levels of volatile organic compound (VOC, or solvent-(ike chemical) contamination remaining that are serving as an ongoing source of ground-water contamination. However, 3M's investigation work and a ground water study done by the City of Woodbury showed that ground-water contamination beneath the s:te is effectively being captured by the barrier well system and is prevented from moving beyond the property boundary. Addifional 3h1 activities have included installing a fence around the property, developing an agreement to restrict site access or site development without MPCA approval and conducting a pilot study to assess the potential use of soil vapor extraction for cleanup of the northeast disposal area. (Soil vapor extraction is a method of vacuuming solvent vapors £rom the soil.) Unfortunately, the pitot fest showed that this cleanup method would not work effectively at the site. � In accordance with a cteanup plan approved by the MPCA in 7uly 1995,� 3M has completed several measures to restore the site and clean up or manage fhe remaining contamination. These measures included confinuing to operate the barrier well system and continuing to regularly sample a network of residentia} wells, barrier wells, and monitoring wells. Progress reports on these activities have been submiried annually to the MPCA, In late 1995, 3�1 re-graded the disposai areas and covered them with Two feet of compacted soil. Then, over a two year period 3M studied various options for cleanup of the northeast disposal area. Seventy cteaiiup technologies or options were evaluaEed to determine their potential � effectiveness at the site. The study identified only two potential cleanup measures that would work well: capping of the disposal areas with a low-permeabiiity soil covex (which had already been completed), and monitored natural attenuation. Natural attenuation has been increasingty accepted by the U.S. Environmental Protection Agency as a cleanup method for organic compounds in ground water. It consists of several natural processes occurring in ground water, sach as: biodegradation (the breakdown of chemicats by bacteria and fungi); dispersion {the tendency of molecules of chemieal to disperse away from the center of eontamination); dilution (the gradual lessening of a chemicaPs concentration due to mixing}; adsorption (the 3M Woodbury Site Update pa9e 2 08/29/98 THU 08:52 b'A% 612 296 8717 MPCA GN'SW DIVISION �004 � Minnesota Pollution Control Agency ""� Metro Distr�cVRemediation SectionNoluntary investigation and Cleanup Program Cleanup/August 1998 tendency for certain chemicals to stick to soil partic(es, rather than remain in ground water); volatilization (the evaporation of chemicals into air spaces in the soil); and stabilization of contaminants. Before monitored natural attenuation is accepted as a cleanup strategy, ground water monitoring must demonstrate that these processes are effectively reducing the levels and amount of organic chemicals in ground water. With the approval of the MPCA staff, 3M has been conducting moniYored natural attenuation studies over the past ] I/2 years, The results so faz indicate that monitored natural attenuation is effectively reducing the volume and concentrations of ground water oontaminants at the site. The combination of three cleanup measures, the barrier well system, monitored natural attenuation, and the low- permeability soil cap, appears to be an effective cleanup stracegy. All of the available infortnation indicates that these measures are cleaning up and/or containing the contamination at the site, as well as protecting human healch and the environment in this area. Currently, 3M is developing a long•range comprehensive management plan for the site. Once completed, this plan will be evaIuated by MPCA staff to ensure ihat future site usage will be consistent with the cteanup measures tliat have beea implemented. What if I have questions? MPCA staff is currently reviewing 3M's final plans for site cleanup and monitoring. If you have questions or concerns, the MPCA encourages you to present them as soon as possible so they can be incorporated into the review process. To voice your comments or to get more information about the siCe, please confact Mike Connolly (651-297-827q) or 7erry Stahnke (651-297-1459) ofthe MPCA's VIC Progxam. 3M Woodbury Site Update Page 3