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HomeMy WebLinkAboutUpdate on Bozeman Solvent Site, Notice of 2009 Vapor Study and Notice of Community Meeting on June 2nd at Bozeman Library Commission Memorandum REPORT TO: Honorable Mayor and Commission Members FROM: Tim Cooper, Assistant City Attorney Chris Kukulski, City Manager SUBJECT: Update on Bozeman Solvent Site, Notice of 2009 Vapor Study, and Notice of Community Meeting on June 2nd at Bozeman Library MEETING DATE: June 1, 2009 SPECIAL PRESENTATION: We will update the Commission on the Bozeman Solvent Site, the project history, the regulatory process, ongoing testing and monitoring, the potential for PCE Vapor Intrusion and the 2009 Vapor Study. Report compiled on: May 29, 2009 Attachments: Power Point Presentation 24 BOZEMAN SOLVENT SITE HISTORY and 2009 VAPOR STUDY Michael G. Ellerd ATC Associates Inc. Bozeman, Montana June 2009 25 AGENDA §Overview §Project History §Regulatory Process §Ongoing Testing & Monitoring §Potential PCE Vapor Intrusion §2009 Vapor Study 26 OVERVIEW §BSS & DNRC Controlled Ground Water Area 27 OVERVIEW §Shallow Groundwater (<50 ft) PCE Impacts as of June 2008 (concentrations >5 µg/L) 28 OVERVIEW §Former Buttrey Shopping Center 29 PROJECT HISTORY §1989, Perchloroethene (PCE) discovered by MDEQ in Nelson Mobile Home Park §1989, alternate water supplies provided and municipal water connections begin §1990 & 1992 Investigations determine former BSC septic system as a source, which was removed in 1992 §1994 & 1995 Investigations determined sewer line behind the BSC as another source, which was replaced in 1994 and 1995 §1992 –1995 Partial excavation of impacted soil during septic system removal and sewer line replacement §1993 –1997, Soil vapor extraction systems operated in source areas §1997, Draft RI report submitted to MDEQ §1999, RI revised and finalized §1999, Semi-annual groundwater monitoring implemented 30 PROJECT HISTORY, Continued §2004 Baseline Risk Assessment submitted to MDEQ §2005 MDEQ granted City and Jewel Food Stores permission to proceed with voluntary bioremediation pilot testing §2006 CVS assumed responsibility for the Bozeman Solvent Site from Jewel Food Stores §2006 Revised Baseline Risk Assessment submitted to MDEQ §2006 Draft Feasibility Study submitted to MDEQ §2006-2007 City & CVS conducted pre-pilot test source area investigations. §2007 City & CVS conduct sub-slab vapor and indoor air sampling at Hastings and CVS §2008 City & CVS begin bioremediation pilot testing at the former BSC §2009 City & CVS conduct follow-up sub-slab vapor and indoor air sampling at Hastings, CVS and Corral West Ranchwear 31 REGULATORY PROCESS §MDEQ CECRA Process for the BSS 32 ONGOING TESTING & MONITORING §Regular groundwater monitoring since 1989 §Monthly, quarterly, semi-annual and annual from 1989 to 1999 §Semi-annual monitoring since 1999 in accordance with MDEQ approved Long Term Monitoring Program •June (~40 wells) and December (~15 wells) §PCE concentrations have and continue to exhibit overall declining trends §For example, PCE at Nelson Mobile Home Park (R-11) •August 1989, 714 µg/L (ppb) •June 2008, 1.5 µg/L (ppb) •MDEQ Water Quality Standard for PCE = 5.0 µg/L (ppb) §2006-2007 BSC source area (pre-pilot test) investigations §Voluntary bioremediation pilot test (currently in progress at the BSC) §Sub-slab vapor and indoor air studies (more on these later) 33 POTENTIAL PCE VAPOR INTRUSION §The issue: §MDEQ recently determined there may be a potential indoor air risk from PCE migrating from groundwater into soil gas in the residential area north (downgradient) of the former Buttrey Shopping Center. §The response: §City and CVS will conduct a phased investigation to evaluate this potential. §But first, some background… 34 POTENTIAL PCE VAPOR INTRUSION §What is PCE? §Tetrachloroethene or perchloroethene or PCE §Volatile organic compound (VOC), i.e., a liquid at room temperature that readily evaporates §Cleaning solvent commonly used in dry-cleaning, auto parts cleaning, and household products such as •Carpet cleaner •Spot remover •Other cleaning products §Occurs in indoor air from variety of sources such as •Recently dry-cleaned clothes •Storage and use of cleaning products •Paper coatings and printing inks •Neighboring commercial uses (auto shops, dry cleaners, etc) 35 POTENTIAL PCE VAPOR INTRUSION §VOCs may migrate into the unsaturated zone from soil or groundwater. §Vapors may migrate through the unsaturated zone into a building through cracks, utility holes, or other openings in foundations. 36 POTENTIAL PCE VAPOR INTRUSION §Previous BSS Vapor & Indoor Air Studies §1997 Groundwater off-gassing study §2007 Employee exposure monitoring §2007 BSC outdoor air, sub-slab soil gas and indoor air studies at CVS & Hastings §2009 follow-up BSC outdoor air, sub-slab soil gas and indoor air studies at CVS and Hastings, and sub-slab and indoor air at Corral West 37 POTENTIAL PCE VAPOR INTRUSION §Results of previous investigations: 1.Nicklin Earth & Water/Agency for Toxic Substances and Disease Registry (ASTDR), 1997: vapor-phase contaminants unlikely to migrate from groundwater to the indoor air of homes or other buildings at concentrations above normal indoor air concentrations. 2.Hygiene Technologies International, 2007: Employee exposure monitoring did not detect PCE in any sample badges worn by employees during normal shifts. 3.Kleinfelder, September 2007: Indoor air concentrations of PCE do not pose an unacceptable health hazard to employees of Hastings or CVS, nor to patrons of those businesses based on EPA indoor air guideline concentrations, which are higher than those found in these businesses. 4.Kleinfelder, March 2009: Results of sampling in CVS and Corral West Ranchwear found sub-slab concentrations generally decreased but that some indoor air VOC concentrations increased, although concentrations are below typical action levels. 38 POTENTIAL PCE VAPOR INTRUSION §However, a recent generic theoretical evaluation by the MDEQ indicated it may be possible for PCE to migrate from the dissolved phase into the vapor phase at concentrations exceeding screening levels at the Bozeman Solvent Site. §In response to this evaluation the City and CVS are proceeding with a phased study of off-site soil vapor conditions. 39 2009 BSS VAPOR STUDY §Phased approach 1.Install soil gas probes in City of Bozeman right-of- way in residential area north of former Buttrey Shopping Center. 2.Then, if warranted from Step 1, install additional soil gas probes adjacent to residences. 3.Only if warranted from Steps 1 and 2, then conduct indoor air sampling to determine if PCE exists in residences north of the BSC above guideline or background concentrations. 40 2009 BSS VAPOR STUDY §First phase, summer 2009 §Install and sample 30 soil gas probes in 15 locations §Probes installed via direct-push along streets and in alleys from the former BSC and Oak Street §Probes installed just above the water table §Samples collected under vacuum in “Summa” canisters §Samples analyzed for PCE §Results evaluated and compared to MDEQ (EPA) residential indoor air screening levels and background indoor PCE concentrations 41 2009 BSS VAPOR STUDY •Proposed First Phase Soil Gas Probe Locations 42 2009 BSS VAPOR STUDY §Typical background residential PCE concentrations: §Historically, dozens of studies have measured PCE in indoor air at a wide range of concentrations; §EPA studies indicate typical background residential PCE concentrations range between approximately 1 and 10 µg/m3 §The mean concentration in another large indoor study was approximately 3 µg/m3 §Another study found a maximum background PCE concentration of approximately 20 µg/m3 §MDEQ residential indoor air screening level §For PCE this level is 0.41 µg/m3 §Therefore background levels must be considered 43 PRESS RELEASE FOR IMMEDIATE RELEASE The City of Bozeman and CVS/pharmacy to Conduct Bozeman Solvent Site Vapor Study - Public informational meeting to be held Tuesday, June 2 - Bozeman, Montana, May 27, 2009: The City of Bozeman (City) and CVS/pharmacy (CVS) announced today that a study will be conducted early this summer to evaluate the potential for vapor migration from groundwater impacted by a former dry cleaner in the neighborhoods north of the Hastings Shopping Center. The study is part of ongoing activities on the Bozeman Solvent Site, the site of an inadvertent release of perchloroethene (PCE) from a former dry cleaning operation located at what was once known as the Buttrey Shopping Center, now known as the Hastings Shopping Center. The PCE release was first discovered in 1989 and has since been regulated by the Montana Department of Environmental Quality (MDEQ). The City and CVS share joint responsibility for the Bozeman Solvent Site. CVS assumed responsibility for the site in 2006 as part of its acquisition of the Osco Drug chain. PCE is commonly detected in residential indoor air and occurs from such things as: dry-cleaned clothes; the use of household cleaning products such as carpet cleaner, spot remover and metal cleaners; paper coatings and printing inks; and proximity to neighboring commercial operations that use PCE such as automobile repair shops and dry cleaners. The City and CVS have seen no evidence to suggest that PCE concentrations in residences in the study area should exceed normal background residential concentrations. Nonetheless, they have proposed to conduct the vapor study to ensure there are no potentially adverse health effects as a result of the Bozeman Solvent Site. The City and CVS will hold a public meeting at 7:00 pm on Tuesday, June 2 in the Community Room of the Bozeman Public Library to provide further information to the public and address questions and/or concerns. The first phase of the vapor study will involve installation and sampling of a series of 30 soil vapor probes in 15 locations along City streets and alleys in a study area between the Hastings Shopping Center and Oak Street in order to evaluate the presence of PCE vapor in the soil above groundwater. If PCE is detected in soil gas above MDEQ screening levels, the second phase of the study will involve installation and sampling of probes adjacent to residences in the study area. If PCE is detected in the first and second phases of the study above MDEQ screening levels, the third phase of the study will involve indoor air sampling in residences in the study area to determine if indoor air PCE concentrations exceed regulatory guidelines or normal background concentrations. The Bozeman Solvent Site has been carefully studied and monitored in the past. By way of background, following discovery of the PCE release in 1989, it was determined that the release occurred through former septic and sewer systems at the Buttrey Shopping Center. These septic and sewer systems were subsequently replaced or removed, during which some PCE impacted soil was removed. Additional PCE was removed through soil vapor extraction in the mid-1990s. Groundwater sampling is conducted on a semi-annual basis to monitor PCE concentrations in groundwater . (more) While the data show that PCE concentrations have and continue to exhibit overall declining trends, the data also indicate residual PCE remains in the source area at the Hastings Shopping Center. Therefore, the City and CVS sought and received approval from the MDEQ to voluntarily proceed with bioremediation pilot testing, a remedial technology that enhances natural destruction of PCE by soil microbes, and that effort is ongoing. In addition, several vapor and indoor air investigations have been conducted at the site: • A 1997 groundwater off-gassing study determined that vapor-phase contaminants are unlikely to migrate from groundwater to the indoor air of homes or other buildings at concentrations above normal indoor air concentrations. • In 2007 an employee exposure monitoring study conducted in Hastings Books and Video did not detect PCE in any sample badges worn by employees during normal shifts. • An outdoor air, sub-slab soil gas and indoor air study at CVS & Hastings, also conducted in 2007, determined that indoor air concentrations of PCE do not pose an unacceptable health hazard to employees of Hastings or CVS, nor to patrons of those businesses. The study’s results were below the EPA’s indoor air guideline concentrations. • A follow-up study in March 2009 in Hastings and CVS, along with space formerly occupied by Corral West Ranchwear, found sub-slab concentrations generally decreased but that some indoor air VOC concentrations increased, although concentrations are below typical action levels. Recently, the MDEQ, using a hypothetical model that was not specific to the Bozeman Solvent Site, indicated it may be possible for PCE to migrate from groundwater into soil vapor at concentrations exceeding screening levels in the residential area north (downgradient) of the Hastings Shopping Center. In response, the City and CVS have proposed to conduct a phased investigation to evaluate this potential, and on behalf of the City and CVS, two environmental consulting firms, ATC Associates Inc. (ATC) and Kleinfelder Inc. (Kleinfelder), will conduct the proposed vapor study. Upon approval of that proposal by the MDEQ ATC and Kleinfelder will proceed with the vapor study in June. ### Media Contacts: Michael Ellerd ATC Associates 406-794-5711 michael.ellerd@atcassociates.com Debbie Arkell, Director of Public Services City of Bozeman 406-582-2315 darkell@bozeman.net Mike DeAngelis CVS/pharmacy 401-770-2645 mjdeangelis@cvs.com