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HomeMy WebLinkAboutReceptor Survey Report r + Minnesota Pollution Control Agency February 19, 1999 RECEIVED Mr. Michael J. Pudil MAR 0 1 1999 President and CEO CITY yr UR®,yp Washington Scientific Industries Inc. 2605 West Wayzata Boulevard Long Lake,Minnesota 55356 RE: Washington Scientific Site II MPCA Project Number VP10021 Dear Mr. Pudil: The Minnesota Pollution Control Agency(MPCA) staff in the Voluntary Investigation and Cleanup(VIC)Unit has been requested to review and provide comments on the"Receptor Survey Results,"dated September 18, 1998, for the Washington Scientific II site, located at 2605 West Wayzata Boulevard in Long Lake(the Site). This and the other reports listed below have formed the basis for this review. 1. "Project Status Report,"prepared by Delta Environmental Consultants(Delta), dated September 28, 1992; 2. "Semi-Annual Ground Water Monitoring Summary Report,prepared by Delta,dated July 26, 1996; 3. "Work Plan Addendum,"prepared by Delta Environmental,dated August 9, 1996; 4. "Supplemental Site Investigation,"prepared by Delta Environmental, dated October 25, 1996; 5. "Semi-Annual Ground Water Monitoring Summary Report,"prepared by Delta,dated February 7, 1997; 6. "Semi-Annual Ground Water Monitoring Summary Report,"prepared by PEER, dated July 25, 1997; 7. "Work Plan for Environmental Investigation,"prepared by PEER, dated August 1, 1997; 8. "Environmental Investigation Report,prepared by PEER, dated November 1, 1997; 9. "Semi-Annual Ground Water Monitoring Summary Report,prepared by PEER,dated January 28, 1998; 520 Lafayette Rd. N.; St. Paul, MN 55155-4194; (612)296-6300(Voice); (612)282-5332(TTY) Regional Offices: Duluth•Brainerd-Detroit Lakes•Marshall•Rochester Equal Opportunity Employer-Printed on recycled paper containing at least 20%fibers from paper recycled by consumers. 1 T 11 7 Mr. Michael J. Pudil Page 2 February 19, 1999 10. "Phase II Investigation Work Plan,"prepared by Barr Engineering,dated May 1, 1998; 11. "Operation and Maintenance Plan, Ground Water Monitoring and Remediation System, prepared by PEER,dated May 1, 1998; 12. "Special Discharge Report- Second Quarter 1998,"prepared by PEER,dated July 17, 1998; 13. "Semi-Annual Ground Water Monitoring Summary Report,"prepared by PEER,dated July 17, 1998; 14. "Remedial Action Plan,"prepared by Barr,dated September 1, 1998; 15. "Receptor Survey Results,"prepared by PEER,dated September 18, 1998; and 16. Various correspondence and monitoring submittals in the MPCA Site file. In 1987, Washington Scientific Industries Inc. (WSI)identified chlorinated solvents in the soil and ground water at the Site on the south portion of its facility during the construction of a parking lot expansion. In 1988, WSI installed a ground water pump-out system as a remedy under the MPCA Resource Conservation and Recovery Act(RCRA)Corrective Action Program. Since that time, WSI has continued to operate the ground water remediation system and submit periodic ground water monitoring reports. In a letter dated June 29, 1998, Sarah Halvorson of Lindquist&Vennum,P.L.L.P. requested on behalf of WSI that MPCA oversight of the ground water response actions and monitoring continue under the administrative oversight of the VIC Program. A letter from the MPCA RCRA project staff on August 10, 1998,effectively transferred continuing oversight of the project to the VIC Program. In response to a request by the MPCA RCRA project staff, WSI has prepared and submitted the "Receptor Survey Results"(the Report),to address questions regarding the location and construction of private ground water supply wells in the vicinity of the Site. The Report also presents a conceptual work plan for installing a ground water sentry well between the Site source contamination and the downgradient residential properties and for working towards a phased shutdown of the ground water pump-out system. Mr. Michael J. Pudil Page 3 February 19, 1999 The Report is hereby approved subject to the modifications presented in Attachment B. Please also note the standard disclaimers in Attachment A. If you have questions regarding this letter, please contact me at (651) 297-5573 or Patrice Jensen at(651) 296-7744. Sincerely, Richard M. Jolley Senior Hydrogeologist Voluntary Investigation and Cleanup Site Remediation Section Metro District RMJ:tac Enclosures cc: Robin Kohn, Washington Scientific Industries Elizabeth Van Zomeran, City of Orono Kenneth Larsen, Peer Environmental Sarah Halvorson, Lindquist& Vennum, P.L.L.P. Crague Biglow, MPCA ATTACHMENT B MODIFICATIONS Washington Scientific II Site MPCA Project Number VP 10021 1. -The Report presents a conceptual plan for installing one additional deep ground water monitoring well along the southern WSI property boundary. Rather than one sentinel well, the MPCA shall require at a minimum two additional sentinel wells. The construction and location of these wells shall be provided to the MPCA staff for review and approval prior to installation. 2. The conceptual plan presented in the Report recommends shutting the ground water pump- out system off and installation of sentinel well(s). Prior to shutting the ground-water pump- out system off,the proposed sentinel wells shall be installed, and a revised ground water monitoring plan shall be submitted to the MPCA for review and approval. The MPCA staff recommends that this revised ground water monitoring plan include a contingency plan for response actions to be taken in the event the ground water plume is found to be migrating beyond an acceptable distance of its current location. 3. Please note, in advance,that as part of the revised ground water monitoring plan noted above, the ground water monitoring frequency shall need to be modified to at least quarterly rather than the current semi-annual frequency,during the year following shutting off the ground water pump-out system. Recommendations for modifying this monitoring frequency may be presented as part of the annual ground water monitoring report. 4. Please note the system should not be dismantled, but only shut off during the proposed initial monitoring evaluation of the pump-out shut-down. Page 1 of I