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HomeMy WebLinkAboutAmended OOC Request Prepared by: 349 Route 28, Unit D W. Yarmouth, Massachusetts 02673 24 Charles Street, South Yarmouth Request to Amend OOC SE 83-2253 Town of Yarmouth Conservation Commission December 2021 Prepared for: Amy MacIsaac 24 Charles Street South Yarmouth, MA 02664 BSC Job #50444.00 December 1, 2021 Town of Yarmouth Conservation Commission 1146 Route 28 South Yarmouth, MA 02664 Attn: Kelly Grant, Conservation Administrator RE: Request to Amend Order of Conditions SE 83-2253, 24 Charles Street, South Yarmouth, Massachusetts, BSC Job #50444.00 Dear Ms. Grant and Members of the Conservation Commission: BSC Group, Inc. (BSC) is pleased to submit this Request to Amend the Order of Conditions SE 83-2253 on behalf of Amy MacIsaac (the Applicant) for the project located at 24 Charles Street, South Yarmouth, Massachusetts (the Site). The approved project consists of the construction of an addition to an existing single-family dwelling in the footprint of a portion of the deck, alterations to the existing deck, and the relocation of the existing septic system further inland (the Project). The homeowner was switching their heat source from oil to natural gas, and found a leak coming from the oil tank. Upon further exploration it was found that a large area beneath the existing single-family home has become contaminated due to the oil leak; please see attached foundation plan showing contaminated area. Also attached with this request is a Phase I Initial Site Investigation/ Tier Classification and Immediate Response Action Status Report #3 from Green Seal Environmental, LLC. Please refer to this report for more detailed information on the leak and contaminated area; specifically, page 14 paragraph 2 for a detailed description of the remedation. In order to remediate the Site, the applicant would like to amend the existing order of conditions. The requested amendment would allow the applicant to remove all contaminated soil from beneath the house and within the existing foundation. The applicant proposes to lift and temporarily move the existing single-family home so that all contaminated material can be removed from the site. To accomplish this, a new foundation wall is proposed in order to support the existing garage while the house is lifted; see attached Site Plan of Land from BSC Group, Inc. The new wall will create ± 89 s.f. of impacts within the 35’-50’ buffer to top of coastal bank. The new foundation wall is the only new proposed impact. After removing all contaminated material, new foundation walls will be poured within the footprint of the existing foundation. Then the house will be placed back on top of the foundation within the footprint of the existing home. All contaminated material will be hauled off to an appropriate disposal site. The limit of work and erosion controls will remain the same as the already approved project because no work is proposed closer to resource areas. All disturbed areas will be restored to pre- Kelly Grant – Yarmouth Conservation 12/1/2021 Page 2 existing conditions once the house is back in place. Included with this request to amend the OOC SE 83-2253 are… 1. Town of Yarmouth AOOC Checklist 2. Certified Abutters List 3. Abutter Notification Letter 4. Phase I Initial Site Investigation/ Tier Classification and Immediate Response Action Status Report #3 from Green Seal Environmental, LLC 5. Site Plan of Land from BSC Group, Inc. 6. Foundation Plan from Apex Engineering 7. Check for Legal Advertising Fee This application is being submitted in accordance with the Massachusetts Wetlands Protection Act and the Town of Yarmouth Wetlands Protections By-law. If you have any questions or require additional information, please contact me at (508) 778 - 8919. Truly yours, BSC Group, Inc. Paul Mancuso, WPIT Environmental Scientist cc: Department of Environmental Protection, Southeast Regional Office, 20 Riverside Drive, Lakeville, MA 02347 Amy MacIsaac, 24 Charles Street, South Yarmouth, MA 02664 Yarmouth Conservation Commission • 1146 Route 28 • South Yarmouth, MA 02664-4492 Tel. (508)-398-2231 Ext. 1288 • Fax (508)-398-0836 • TTD# (508) 398-2231 Revised February 2016 Administrative Checklist Request to Amend an Order of Conditions General Information: The letter must be submitted two weeks prior to the next scheduled Conservation Commission meeting. No new information may be accepted into the Commissioner’s pack et a week before the meeting. Failure to follow the Administrative Checklist guidelines shall result in an Administrative Incomplete Application and will not be advertised for a Public Hearing. Contact the Conservation office if you need assistance. For more information, refer to Wetlands & Waterways Program DWW Policy 85-4. Submitting an Application: 1 original letter requesting an amendment. The request shall include the DEP file number, project location, specific narrative of the proposed change and current applicant/homeowner information. 1 original and 7 copies of the updated plan, folded separately, right side out with title. All plans shall reference NAVD1988 unless otherwise noted. Landscape plans shall be detailed to show proposed and existing conditions, native species, size and spacing. A pdf of original letter, plan, and other supporting information emailed to kgrant@yarmouth.ma.us. Please put the property’s street address in the pdf file na me. A 100’ radius map, current abutters list and abutters notification identifying the property owners who are to be notified per 310 CMR 10.00. Abutters list must be certified by the Town Assessor’s office. The Assessor’s office requires 7 days advance notice. Submit Certified Mail Receipts (PS Form 3800) for all abutters. Submit Certified Mail Receipts for Massachusetts Natural Heritage and Endangered Species Program and Massachusetts Division of Marine Fisheries if applicable. Alternatively, you may visit their websites for electronic filing information. If filed electronically, please copy kgrant@yarmouth.ma.us. Legal ad fee - check payable to “Town of Yarmouth”. (Refer to Fee Schedule at https://www.yarmouth.ma.us/696/Filing-Forms) Waterway’s jurisdiction – Any coastal projects such as, but not limited to, docks, piers, bulkheads, revetments, dredging and boardwalks shall require submittal of all Notice of Intent, plans and supplemental information to the Town of Yarmouth Waterways/Shellfish Committee via the Natural Resources office by certified mail or in-hand delivery. The applicant or his/her representative must provide the Conservation office proof that this has been done or the filing will not be accepted. 1 pdf of the letter, plan and other supporting information shall be sent VIA EMAIL to DEP, Southeast Region at SERO_NOI@mass.gov with a subject line showing “YARMOUTH - RAOC – MassDEP 7-Digit File Number” and copied to kgrant@yarmouth.ma.us. We must receive a copy of this email as proof that it has been sent to DEP. DEPARTMENT OF CONSERVATION X X X X X N/A X N/A X 70/ 115/ / / WAHNSCHAFFT OLIVER ZANAPALIDOU RACHEL 34 CHARLES ST SOUTH YARMOUTH , MA 02664 70/ 114/ / / LEAHY JAMES K LEAHY DEBORA J 661 LIBERTY ST BRAINTREE , MA 02184 70/ 112.1/ / / THIELMAN WILLIAM J III C/O GRIECO JOHN E 13 STOCKWELL LN SOUTHBOROUGH , MA 01772 70/ 104/ / / RICE ALLISON BELCHER ELIZABETH & AARON 17 CHARLES ST SOUTH YARMOUTH , MA 02664 70/ 113/ / / MACISAAC AMY TRS AMY MACISAAC REV TRUST 24 CHARLES ST SOUTH YARMOUTH , MA 02664 70/ 98/ / / BANK OF AMERICA N A TR PO BOX 460329 DEPT 909 HOUSTON , TX 77056 70/ 97/ / / WOJNAR STANLEY J WOJNAR APHRODITE M 14650 DURBIN ISLAND WAY ST JOHNS , FL 32259 70/ 96/ / / BARR JOHN D NORTON WENDY JANE 29 BASS RIVER RD SOUTH YARMOUTH , MA 02664 70/ 95/ / / MALLOY PAUL F MALLOY SALLY M 1 ALBERMARLE RD NEWTONVILLE , MA 02460 70/ 94/ / / MALLOY PAUL F MALLOY SALLY M 1 ALBERMARLE RD NEWTONVILLE , MA 02640 70/ 100/ / / GOW JAMES E GOW BARBARA A 11 BRYN MAWR AVE AUBURN , MA 01501-1620 70/ 99/ / / PAZAKIS ROSETTO M PAZAKIS BARBARA E 17 BASS RIVER RD SOUTH YARMOUTH , MA 02664-3125 NOTIFICATION TO ABUTTERS UNDER THE MASSACHUSETTS WETLANDS PROTECTION ACT & TOWN OF YARMOUTH WETLAND BY-LAW, CHAPTER 143 In accordance with the second paragraph of the Massachusetts General Laws Chapter 131, Section 40, you are hereby notified of the following: A. The name of the applicant is Amy MacIssac B. The applicant has filed a Request to Amend an Order of Conditions with the Yarmouth Conservation Commission, seeking permission to remove, fill, dredge or alter an Area Subject to Protection under the Wetlands Protection Act (MGL c. 131 s. 40 & Town of Yarmouth Wetland By-Law, Chapter 143). C. The address of the lot where the activity is proposed is 24 Charles Street, South Yarmouth D. Proposed work is to remove all contaminated material from the Site. A leak from an old oil tank has contaminated soil at the Site. E. Copies of the Request to Amend an Order of Conditions may be examined at the Yarmouth Town Hall at the Conservation Commission office between the hours of 9:00 a.m. and 4:00 p.m. Monday thru Friday. For more information, call (508) 398-2231 ext. 1288. F. Copies of the Request to Amend an Order of Conditions may be obtained from the applicant’s representative. Applicant’s representative’s phone number: 508-778-8919 G. Information regarding the date, time and place of the public hearing may be obtained by calling the Yarmouth Conservation Commission office at (508) 398-2231 ext. 1288 H. Person sending this notification (representative) Name Paul Mancuso Address 349 Route 28, Unit D Town West Yarmouth State MA Zip 02673 Telephone 508-778-8919 Note: • Notice of the public hearing, including date, time and place will be published at least five (5) days in advance in a newspaper of general circulation. • Notice of the public hearing, including date, time and place will be posted in the Town Hall not less than forty-eight hours in advance. • You may also contact the Southeast Regional Office of the Department of Environmental Protection at (508) 946-2800 for more information about this application. Green Seal Environmental, LLC 114 State Road, Bldg. B, Sagamore Beach, MA 02562 T: 508.888.6034 F: 508.888.1506 www.gseenv.com 1 MassDOT Certified DCAMM Certified MCSS-2001-0001 November 8, 2021 Mr. John Handrahan, Chief – Brownfields and C&E Massachusetts Department of Environmental Protection (MassDEP) Southeast Regional Office (SERO)/Bureau of Waste Site Cleanup (BWSC) 20 Riverside Drive Lakeville, MA 02347 RE: PHASE I INITIAL SITE INVESTIGATION/TIER CLASSIFICATION and IMMEDIATE RESPONSE ACTION STATUS REPORT #3 MacIsaac Residential Property - RTN 4-28586 24 Charles Street – South Yarmouth, MA 02664 (Parcel ID:70/113) Dear Mr. Handrahan, Green Seal Environmental, LLC (GSE) has prepared the following Phase I Initial Site Investigation report and Supporting Documentation to support Tier 1 Classification at the subject property at the one-year anniversary of Release Notification in accordance with the provisions of 310 CMR 40.0483 and 40.0500; respectively. This document also includes an Immediate Response Action (IRA) Status report beyond those previously submitted; the most recent being September 14, 2021. It is our intent to continue the IRA concurrent with Comprehensive Response Actions with the work proposed in the Phase II Scope of Work presented herein. This Phase I Investigation, as the basis of Tier I Classification, relies heavily on the environmental assessment activities and risk assessment undertaken as part of the ongoing IRA following the initial remedial response conducted for the removal of impacted soils from the release area undertaken in the period from December 2020 to January 2021. These response actions were conducted under the previous Licensed Site Professional (LSP) of record for the release. Under the verbal approval of MassDEP for the removal of up to 200 yards of impacted soils, excavation activities resulted in the generation of some 28.5 tons (20 yards) of remedial waste from a roughly 10 foot x 8 foot x 8 foot (D) area. On January 7, 2021, light non-aqueous phase liquid (LNAPL) was measured in monitoring well MW-1, located upgradient of the release area, and verbal approvals were extended for the removal of up to 500 gallons of LNAPL and oily water. The excavation was not advanced into the water table below 8 feet as apparently based on structural concerns and shoring capacity to maintain a safe work space. As a result, residually impacted soils remain within the capillary fringe of the release area and no LNAPL recovery was made other than a drum of oily liquids and spent absorbents. Subsequent assessment under the Successor LSP indicted significant risk associated with residual soil and groundwater impacts as driving vapor intrusion into an occupied dwelling as a Critical Exposure Pathway (CEP). Piping left within the backfilled excavation was used to construct a sub-slab vapor extraction system as NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 2 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 was piloted and verbal authorization granted by the MassDEP for the operation and maintenance of this system as an active exposure pathways mitigation system. The efficacy of this system has been demonstrated by subsequent indoor air testing as a temporary measure. Additionally, verbal authorization to extend the removal of up to 2,500 gallons of LNAPL and oily water for further source reduction was requested and granted. Several attempts were made in the most recent reporting period to remove oily water and LNAPL from the release area using the wellpoint (IW-1) left within the area of excavation. Such efforts had limited success with the recovery of 258 gallons of oily water with globules of free phase liquid. Such poor recovery is attributed to the low permeability of the partly silty very fine sands in the upper aquifer and the design of the well as a 1¼ inch driven galvanized well. Although all substantial hazards are mitigated under current conditions and engineering controls, an IRA Status Report for additional aggressive soil removal is included within this Phase I/Tier Classification report. Such is intended under the existing verbal approvals with a Permanent Solution objective as the most effective and desired remedial option in a review of remedial alternatives. Such work is currently being planned, contracted and locally permitted at the time of this filing. In accordance with the provisions of 310 CMR 40.0810(6), the scope and level of detail employed in this Phase I Investigation is commensurate with the nature and complexity of the Disposal Site, wherein a known source of petroleum contamination, from a single release, occurred at a residential dwelling and the hydrogeologic conditions, solute fate and exposure pathways have been investigated throughout the IRA, as summarized herein. This work has been, and continues to be conducted under LSP oversight in a manner consistent with the Massachusetts Contingency Plan (MCP) Response Action Performance Standards (RAPS), pursuant to 310 CMR 40.0191 and the QA/QC policies of GSE. The facts and statements herein are, to the best of our knowledge, a true and accurate representation of the Site activities, remedial response actions and environmental conditions associated with the project to date. ENVIRONMENTAL SETTING AND PROPERTY DESCRIPTION [Refer to Appendix A] The subject property is a 0.79-acre parcel of land at 24 Charles Street in South Yarmouth, Massachusetts, owned by MacIsaac Amy Trustee/Amy MacIsaac Rev Trust, and currently used as a primary residence. The Town of Yarmouth identifies the property as Parcel ID 70-113-10256 as some 1,500 feet north of the Bass River Bridge in South Yarmouth at the West Dennis Town line. According to the Town of Yarmouth Assessor’s database, the property is improved upon by a single-story, single-family residence, with a living area of 1,928 square-feet, constructed in 1945. The dwelling has a garage with living space upstairs and a walkout basement. The improvements include a wooden deck, landscaped areas, and a gravel driveway [Refer to Figure 1 – Appendix A]. Until December 10, 2020, oil heating was used and the heating oil was stored in the basement in an aboveground storage tank (AST), original to the property. In, or around November 6, 2020, the sub-slab fuel line connecting the oil tank to the furnace leaked causing a 225+ gallon release to the environment as resulting in soil and groundwater impacts underlying that portion of the dwelling between the former tank and furnace and as extending to the front entrance area. The extent of soil and groundwater impacts at the Disposal Site is a portion of the subject property underlying a portion of the dwelling footprint and extending to the west under the driveway area in an approximate 30-foot x 30-foot area (900 square feet). It also includes the area of excavation and exterior monitoring well MW-1 [Refer to Site Plan – Appendix A]. NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 3 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 According to the 2018 USGS topographic map (Dennis, Massachusetts quadrangle), the property is situated approximately 15 feet above the mean sea level on the western portion (front of the property); and slopes down into the 100-year flood zone as waterfront property abutting the Bass River tidal estuary. The subject residential property is surrounded by similar high density residential properties to the north, west, and south. High density commercial development is to the south along Route 28 as a State Highway and transportation corridor. The subject property and the surrounding properties are all serviced by an extensive municipal water system with no potable wells within 500 feet of the Site and neither the subject property or Site fall within any designated Zone II – Wellhead Protection area nor Zone A of any surface water reservoir. There is no municipal sewer in the area and the subject and abutting properties are on private septic systems. A stormwater drain is located along the southern property boundary pursuant to an easement agreement with the Town of Yarmouth, and the outfall is located on the subject property. Based on the Mass GIS Priority Resource mapping overlay and Phase I Site Assessment Map, the property categorically falls within the Cape Cod Sole Source Aquifer and as such the GW-1, Method 1 – Risk Characterization drinking water standards would apply [Refer to Figure 2 – Appendix A]. These standards for drinking water ingestion exposure are overstated in the area of the Site as a high-density residential area abutting a tidal estuary wherein the density of development and potential source of pollutants from private sewage discharge and threat of salt water intrusion preclude the development of a public water supply. Notwithstanding, further considered under the provisions of 310 CMR 40.0932(5), the GW-1 standards are considered under the review of additional remedial response measures under the IRA to absolve significant exposure risks to human and environmental receptors identified. Additionally, based on the depth to groundwater at approximately 8-9 feet below grade in the area of the release and footprint of the occupied residential dwelling, the GW-2 and GW-3, Method 1 – Risk Characterization standards are considered in the evaluation of Significant Risk. Based on soil impacts within the release area being below a permanent structure or at depths greater than 4-feet below the existing grade, the S-2 and S-3/GW-1, GW-2 and GW-3 soil criteria is considered under existing conditions. The S-1/GW-1, GW-2 and GW-3 criteria is further considered under the foreseeable future use and activities at the Site. Sensitive Receptors Human receptor groups at the property include residents, visitors (adults and children), and subsurface utility or construction workers. As noted, based on soil accessibility, frequency and intensity of use, under current conditions as below the concrete basement floor at depth, the exposure threat to residually impacted soils via ingestion and dermal contact are minimal as is ingestion exposure threat for the drinking of impacted groundwater. The primary exposure consideration under current conditions is the potential for vapor intrusion and inhalation associated with the residual soil and groundwater impacts as is being addressed by engineering controls for the sealing of the basement floor and use of a sub-slab venting system wherein indoor air testing shows that the system is effective in the control of this CEP and no substantial or imminent hazards are documented by the testing of indoor air conducted to allow for occupancy of the residential dwelling. The Yarmouth Health Department (HD) reported that a well is located on 8 Bass River Road, approximately 340 feet northwest of the subject property. Upon contacting the Yarmouth Water Department, a water service was confirmed and the status of the well was determined to be for irrigation only. As such, no protected water supplies (potable wells, Zone II areas, Interim Wellhead Protection Areas or Zone A surface water reservoirs) are present within 500 feet of the property. The subject property is connected to a private septic system and municipal water services are provided to the subject property and the surrounding area. NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 4 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 As noted, the Bass River runs along the eastern boundary of the subject property and is considered by established Site-specific groundwater flow direction to be the most sensitive environmental receptor with noted tidal flats and Massachusetts Natural Heritage & Endangered Species Program estimated rare wetland wildlife habitat within 250 feet of the release area. Based on plans prepared by BSC Group, and approved by the Yarmouth Conservation Commission, the release is some 120 feet from the edge of the Salt Marsh but falls within the 50 foot buffer zone for the defined Coastal Bank and as within 50 feet of the AE (EL) 100-year flood zone. All work within the release area is subject to Conservation Commission jurisdiction. Prior work was conducted with the benefit of communications with the Conservation Agent under an Emergency (NOI) Certification issued September 9, 2021. Moving forward, additional remedial response actions will be framed as an amendment to the existing Notice of Intent and Order of Conditions SE83-2253 as previously issued for the proposed addition to the rear of the house and upgrade of the septic system. IRA STATUS III [RTN4-28586] Background/Historic IRA Activities On October 22, 2020, approximately 213 gallons of oil were delivered to the subject residential property at 24 Charles Street in South Yarmouth, MA. On the evening of November 5, 2020, the homeowner noticed that hot water and heat were not available, and contacted an oil-burner service company. The oil-burner service technician conducted an inspection on the morning of November 6, 2020, and determined that the AST was out of oil. The fuel oil company was called and an additional 228.9 gallons were delivered on November 6, 2020, at approximately 9:00 am. The fuel company was unable to prime the furnace and restart it. The oil- burner technician was called again and upon inspection he advised the homeowner that the fuel oil supply line was the likely issue, and he shut off the supply line in the late morning. On November 6, 2020, the sub-slab supply line was decommissioned, an overhead oil supply line was installed, and the Yarmouth Fire Department (FD) was notified of the loss of approximately 200 gallons of oil. The Yarmouth FD notified the Yarmouth HD. The FD and HD met with the homeowner and the oil-burner technician and advised the homeowner to hire an LSP. However, no Notification under a 2-Hour Condition was advised or otherwise made. On November 9, 2020, the homeowner contracted with GSE to conduct preliminary investigations to qualify Notification and Remedial Response liabilities. On November 10, 2020, GSE conducted a site inspection and conducted two shallow borings through the concrete slab near the oil-burner and encountered grossly impacted soils as confirming a release to the environment. After confirming that the MassDEP had not been notified by others, GSE notified the MassDEP of the 2-Hour release condition on November 11, 2020. At the time of Notification, verbal approval for the removal of up to 200 yards of impacted soils was approved. On December 15 and 16, 2020, Trident Environmental Group, LLC of Norfolk, Massachusetts, (Trident) conducted a limited soil removal under GSE oversight to reveal the sub-slab fuel supply line, and to preliminarily assess the extent of petroleum impacts in soil. On December 15, 2020, a 5-foot by 5-foot section of the concrete slab was removed. Following the removal of the slab, the underlying soil was removed using hand tools to expose the decommissioned underground fuel supply line and nearby septic pipe. A ruptured protective sleeve was observed on the fuel line. The fuel line was comprised of two sections connected with a threaded joint. Oil was observed along a portion of the exposed length of the supply line and around the joint. Petroleum staining was observed on the soil in the vicinity of the joint and along the supply line and gross soil impact was noted to a depth of at least 5 feet below the basement slab. On December 16, 2020, additional soil removal was conducted to assess the extent of petroleum impacts. The overall depth of the NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 5 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 excavation was approximately 14 inches below the concrete slab, except in the middle area, where the excavation was advanced to an additional 2 feet. Approximately 1.4 cubic yards of soil were removed at this time and stored in 55-gallon drums. In the period between December 28, 2020 and January 5, 2021, GSE performed a series of interior and exterior borings to define the extent and magnitude of soil impacts and for the purpose of installing monitoring wells for groundwater sampling and analysis. GSE advanced three interior soil borings (HB-3 through HB-5) beneath the basement floor slab (bs) up to approximately 9 feet and two shallower borings, HB-6 and HB-7, and screened soil samples with a photoionization detector (PID). Total organic vapor (TOV) readings at HB-3 were greater than 300 part per million by volume (ppmv) between 3.5 to approximately 7 feet, where the boring was terminated. A TOV reading of >100 ppm was reported at HB-4 at the groundwater interface at 8 feet as confirming groundwater impact. The soil boring HB-5 was terminated at approximately 6 feet below the slab due to refusal. A maximum TOV reading of 5.7 ppmv was recorded in HB-5 at the 2-4-foot interval. As such, HB-1, HB-2 and HB-3 represented a targeted area of gross soil impact to the groundwater interface for additional soil removal between the former oil tank and burner which would require extensive shoring. On January 5, 2021, six exterior soil borings (SB-1 through SB-6) were installed to depths of up to 20 feet below ground surface (bgs) using direct-push methodology for the installation of monitoring wells. Soil samples were screened with a PID and soil classification was noted. The soil was primarily classified as very fine to coarse sand with varying amounts of gravel and fine silt, except for a band of dense clayey silt at all but one boring location. The layer of clayey silt was observed at approximate depths ranging between 12 to 17 feet bgs. Elevated TOV readings, exceeding 100 ppmv, were recorded at soil boring SB-1 (MW-1) at depths between approximately 16 and 20 feet bgs corresponding with the groundwater interface. Soil samples from this location reported petroleum hydrocarbon impacts greater than the applicable Method 1 standards at this location where LNAPL was present. All soil borings were completed as one-inch flush mount monitoring wells. On January 7, 2021, the six newly installed wells were developed. During well development, LNAPL thickness of 0.01 feet was detected in monitoring well MW-1. Subsequent groundwater gauging and site-specific groundwater flow computations show this well as upgradient of the release area and impact is attributed to LNAPL travel above the silty clay horizon. During subsequent well gauging events conducted in January, March, and June, LNAPL was not detected in any of the six monitoring wells and with the exception of MW-1, none of the other monitoring wells reported any groundwater impacts. On January 21, 2021, additional concrete slab was removed by Trident in preparation for removal of petroleum-contaminated soil using a vacuum excavator (vactor) from an approximately 6-feet wide, 9-feet long, and 9-feet deep area under verbal authorizations granted by MassDEP. Between January 25 and 27, 2021, excavation of soil was conducted via vactor and hand tools. For structural safety, a timber shoring box designed by Apex Engineering Co., Inc. of Rochester, Massachusetts, was constructed on-site and driven in by Trident’s subcontractor, 38 Excavation, Inc. A total of 25.08 tons of contaminated soil were removed and staged on-site in vactor boxes. The excavation was advanced to approximately 8.5 feet, and apparently based on structural concerns and worker safety, it was not advanced further. Soil samples were collected from the excavation side walls by drilling holes through the sheathing of the shoring box at depths ranging between 4.5 feet and 8.5 feet below the slab. Soil samples were also collected from the bottom of the excavation. The analytical data for the endpoint soil sampling is presented on Table 1 below. NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 6 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 On February 23, 2021, the excavation was prepared for backfilling by removing the accumulated oily water and installing infrastructure for future remediation efforts. A drum pump was used to remove approximately 20 gallons of oily water accumulated at the base of the excavation. The removed oily water was stored in a drum. A 1 ¼-inch diameter galvanized well with 2 feet of 0.010 slotted stainless steel well screen was driven in the northeastern corner of the excavation for future groundwater injections or LNAPL extraction. The well-screen was driven using a 4-inch PVC pipe to approximately 4- feet below the excavation base. The well point was then extended above the basement floor. The bottom of the excavation was then leveled and absorbent pads were used to remove the minor LNAPL accumulation. The excavation was backfilled with ¾-inch native sub- angular stone to approximately 6- feet below the slab. Two 5-foot long, 2-inch diameter, 0.020-inch slotted PVC screens were placed horizontally in the excavation. The top of the stone was covered with a sheet of vapor barrier and further backfilled with excavatable flowable fill by Trident and its subcontractors on March 2, 2021. The impacted soils generated were transported to Ondrick Materials & Recycling, LLC, of Chicopee under a Bill of Lading on January 27 and February 26, 2021. A total of 25.08 tons was transported for asphalt recycling as representing some 17 yards taken from the area of excavation in the basement utility room under the footprint of the dwelling. The drum of oily water and absorbent pads were transported offsite by Clean Harbors on March 1, 2021 to Spring Grove Resource Recovery in Cincinnati, OH under a duly executed Uniform Hazardous Waste Manifest. The IRA Status Report #1 for the project was filed on March 11, 2021 and did not include the March 9, 2021 soil or groundwater analytical results. On April 12, 2021, GSE personnel, including the then LSP of Record, made an inspection of the property to conduct indoor air testing in consideration of dwelling occupancy. This testing indicated that there was significant degradation of the indoor air as a result of the assessment and soil removal activities and the existing 2 foot slotted screen within the backfilled excavation was used for the construction and piloting of a sub-slab venting system to allow for dwelling occupancy. The then LSP submitted a Notice of LSP Termination as filed on May 19, 2021 as expressing the end of LSP Oversight for the subject RTN on May 14, 2021. NETLAB Case Number: 1A28045 Lab Sample Number: Date Sampled: Date Received: Parameter Units Sample Result Reporting Limit Sample Result Reporting Limit Sample Result Reporting Limit Sample Result Reporting Limit Sample Result Reporting Limit Sample Result Reporting Limit Sample Result Reporting Limit Sample Result Reporting Limit Sample Result Reporting Limit Sample Result Reporting Limit Sample Result Reporting Limit Method 1 S-1 & GW-1 Extractable Petroleum Hydrocarbons (EPH) Unadjusted C11-C22 Aromatic Hydrocarbons mg/kg 586 13.5 2130 6.95 16.2 6.81 ND 6.63 11 6.62 70.7 6.53 2320 6.79 3940 14.5 87.9 8.76 497 8.37 547 8.42 Naphthalene mg/kg 1.87 0.67 8.32 0.34 ND 0.34 ND 0.33 ND 0.33 0.33 0.32 5.55 0.34 8.59 0.72 ND 0.43 1.55 0.41 2.3 0.42 4 2-Methylnaphthalene mg/kg 7.78 0.67 11.9 0.34 ND 0.34 ND 0.33 ND 0.33 0.96 0.32 6.73 0.34 28.7 0.72 0.89 0.43 4.4 0.41 5.63 0.42 0.7 Phenanthrene mg/kg 3.69 0.67 0.72 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 11.3 0.34 1.07 0.72 ND 0.43 2.45 0.41 2.79 0.42 10 Acenaphthene mg/kg 1.18 0.67 ND 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 3.48 0.34 6.02 0.72 ND 0.43 0.79 0.41 0.92 0.42 4 Acenaphthylene mg/kg 1.23 0.67 4.57 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 2.36 0.34 3.03 0.72 ND 0.43 ND 0.41 ND 0.42 1 Fluorene mg/kg ND 0.67 1.15 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 1.02 0.34 4.54 0.72 ND 0.43 ND 0.41 ND 0.42 1000 Anthracene mg/kg 1.7 0.67 10.2 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 4.15 0.34 ND 0.72 ND 0.43 1.02 0.41 1.13 0.42 1000 Fluoranthene mg/kg ND 0.67 ND 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 ND 0.34 ND 0.72 ND 0.43 ND 0.41 ND 0.42 1000 Pyrene mg/kg ND 0.67 ND 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 ND 0.34 ND 0.72 ND 0.43 ND 0.41 ND 0.42 1000 Benzo(a)anthracene mg/kg ND 0.67 ND 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 0.88 0.34 1.67 0.72 ND 0.43 ND 0.41 ND 0.42 7 Chrysene mg/kg ND 0.67 ND 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 ND 0.34 ND 0.72 ND 0.43 ND 0.41 ND 0.42 70 Benzo(b)fluoranthene mg/kg ND 0.67 ND 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 ND 0.34 ND 0.72 ND 0.43 ND 0.41 ND 0.42 7 Benzo(k)fluoranthene mg/kg ND 0.67 ND 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 ND 0.34 ND 0.72 ND 0.43 ND 0.41 ND 0.42 70 Benzo(a)pyrene mg/kg ND 0.67 ND 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 ND 0.34 ND 0.72 ND 0.43 ND 0.41 ND 0.42 2 Indeno(1,2,3-cd)pyrene mg/kg ND 0.67 ND 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 ND 0.34 ND 0.72 ND 0.43 ND 0.41 ND 0.42 7 Dibenz(a,h)anthracene mg/kg ND 0.67 ND 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 ND 0.34 ND 0.72 ND 0.43 ND 0.41 ND 0.42 0.7 Benzo(g,h,i)perylene mg/kg ND 0.67 ND 0.34 ND 0.34 ND 0.33 ND 0.33 ND 0.32 ND 0.34 ND 0.72 ND 0.43 ND 0.41 ND 0.42 1000 C9-C18 Aliphatic Hydrocarbons mg/kg 915 13.5 4630 69.3 33.7 13.6 ND 13.2 17.5 13.2 61 13 4930 67.7 12300 144 220 17.5 1230 16.7 1230 16.8 1000 C19-C36 Aliphatic Hydrocarbons mg/kg 251 13.5 1270 69.3 ND 13.6 ND 13.2 ND 13.2 24.3 13 1610 67.7 3810 144 66.8 17.5 362 16.7 348 16.8 3000 C11-C22 Aromatic Hydrocarbons mg/kg 568 13.5 2090 6.95 16.2 6.81 ND 6.63 11 6.62 69.4 6.53 2280 6.79 3890 14.5 87 8.76 487 8.37 534 8.42 1000 Volatile Petroleum Hydrocarbons (VPH) Unadjusted C5-C8 Aliphatic Hydrocarbons mg/kg 27.9 5.3 131 6 ND 5.3 ND 5.3 ND 5.3 22.3 5.3 342 53.7 586 59.6 22.8 8.5 126 8.3 50 8.1 Unadjusted C9-C12 Aliphatic Hydrocarbons mg/kg 228 5.3 1680 23.9 10.2 5.3 ND 5.3 ND 5.3 221 5.3 2110 53.7 3230 59.6 197 8.5 706 8.3 332 8.1 Benzene mg/kg ND 0.3 ND 0.3 ND 0.3 ND 0.3 ND 0.3 ND 0.3 ND 2.7 ND 3 ND 0.4 ND 0.4 ND 0.4 2 Ethylbenzene mg/kg 0.8 0.3 4.1 0.3 ND 0.3 ND 0.3 ND 0.3 0.6 0.3 8.6 2.7 20 3 0.6 0.4 3.8 0.4 1.5 0.4 40 Methyl t-butyl ether (MTBE)mg/kg ND 0.05 ND 0.06 ND 0.05 ND 0.05 ND 0.05 ND 0.05 ND 0.5 ND 0.6 ND 0.08 ND 0.08 ND 0.08 0.1 Naphthalene mg/kg 1.8 0.5 6.7 0.6 ND 0.5 ND 0.5 ND 0.5 1.5 0.5 7.1 5.4 19.6 6 ND 0.8 5.5 0.8 1.5 0.8 4 Toluene mg/kg 0.4 0.3 3.6 0.3 ND 0.3 ND 0.3 ND 0.3 ND 0.3 5.7 2.7 14.6 3 ND 0.4 3.2 0.4 1.2 0.4 30 m&p-Xylene mg/kg 2 0.5 11.4 0.6 ND 0.5 ND 0.5 ND 0.5 1.6 0.5 24.2 5.4 59.4 6 1.4 0.8 11.2 0.8 4.1 0.8 see below o-Xylene mg/kg 1 0.5 5.3 0.6 ND 0.5 ND 0.5 ND 0.5 0.8 0.5 11.6 5.4 28.1 6 ND 0.8 4.9 0.8 1.8 0.8 see below Total xylenes mg/kg 3 0.5 16.7 0.6 ND 0.5 ND 0.5 ND 0.5 2.4 0.5 35.8 5.4 87.4 6 1.4 0.8 16.2 0.8 5.9 0.8 400 C5-C8 Aliphatic Hydrocarbons mg/kg 27.5 5.3 127 6 ND 5.3 ND 5.3 ND 5.3 22.3 5.3 336 53.7 571 59.6 22.8 8.5 123 8.3 48.8 8.1 100 C9-C12 Aliphatic Hydrocarbons mg/kg 172 5.3 1290 6 10.2 5.3 ND 5.3 ND 5.3 168 5.3 1630 53.7 2380 59.6 155 8.5 517 8.3 254 8.1 1000 C9-C10 Aromatic Hydrocarbons mg/kg 52.6 5.3 369 23.9 ND 5.3 ND 5.3 ND 5.3 49.7 5.3 433 53.7 744 59.6 39.1 8.5 169 8.3 70 8.1 100 TABLE 1: ENDPOINT ANALYTICAL SUMMARY VS METHOD 1 - RISK CHARACTERIZATION STANDARDS (JANUARY 2021) MacIsaac: 24 Charles Street - South Yarmouth, MA RTN4-28586 PURPLE = CONCENTRATIONS EXCEEDING THE METHOD 1 RISK CHARACTERIZATION STANDARDS EX-B16 (9.5') 1A28045-11 1/27/2021 15:30 1/28/2021 13:31 EX-B14 (9.5') 1A28045-09 1/27/2021 15:20 1/28/2021 13:31 EX-B15 (9.5') 1A28045-10 1/27/2021 15:25 1/28/2021 13:31 EX-S3 (4.5') 1A28045-07 1/27/2021 14:28 1/28/2021 13:31 EX-S4 (8.0') 1A28045-08 1/27/2021 14:35 1/28/2021 13:31 EX-S5 (4.5') 1A28045-05 1/27/2021 15:06 1/28/2021 13:31 EX-S6 (8.0') 1A28045-06 1/27/2021 15:14 1/28/2021 13:31 EX-S7 (4.5') 1A28045-03 1/27/2021 14:56 1/28/2021 13:31 EX-S8 (8.0') 1A28045-04 1/27/2021 15:01 1/28/2021 13:31 EX-S1 (4.5') 1A28045-01 1/27/2021 14:45 1/28/2021 13:31 EX-S2 (8.0') 1A28045-02 1/27/2021 14:50 1/28/2021 13:31 NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 7 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 The current LSP of Record was engaged by GSE on June 21, 2021 and subsequently assigned to the project and made a thorough review of the public record documentation and internal files. The Successor LSP made initial contact with the property owner the week of July 5, 2021 with the benefit of the June 24, 2021 indoor air testing results as indicating that an Imminent Hazard did not exist and that under Method 3, the dwelling had been occupied with no apparent significant risk as dependent on use of engineering controls. As such the need to obtain verbal approvals for the operations and maintenance of the sub-slab venting system was identified as an active remedial system. Additionally work within jurisdiction of the Wetland Protection Act jurisdiction needed to be approved by the Yarmouth Conservation Commission. Off-gas granular activated carbon (GAC) treatment was added and an onsite meeting with the Yarmouth Conservation agent and the MassDEP case officer were arranged. These meetings were used for discussion of the project moving forward wherein outstanding issues for IRA verbal approvals of an active remedial system, local conservation commission jurisdictional approvals and planned assessment activities for consideration of exposure risks were discussed. The result of such meetings was verbal authorization was provided to operate, maintain and monitor the existing sub-slab venting system and an Emergency Certification for work completed to date was issued allowing 60 days for a formal filing of an Amendment to the existing Notice of Intent for future remedial response activities, wherein aggressive soil removal and in-situ treatment were remedial alternatives being evaluated with the benefit of quarterly indoor air testing, quarterly monitoring well sampling and groundwater analysis and supplemental soil testing at the perimeter of the area of the former excavation. Monitoring wells MW-1, MW-2, MW-3 and MW-4 were sampled on July 6, 2021, and analytical results reported all fractional EPH/VPH compounds and fractional analytes at MW-2, MW-3, and MW-4 as non-detect wherein the reporting limit concentrations were less than the strictest GW-1, Method 1 – Risk Characterization standards. Laboratory analysis for MW-1 again reported significant impacts above GW-1, Method 1 Risk Characterizations standards. Such concentrations were greater than previously reported in March 2021 and in the case of the C9 to C18 aliphatic compounds, also greater than the GW-2, Method 1 standards. The IW-1 well was also sampled and reported only low-level impacts. This well was found to be fully penetrating with top of screen some 2-feet below the groundwater interface. As such, the laboratory analysis of this well following installation and testing in July 2021, were not representative of the extent of groundwater impacts wherein the presence of LNAPL was noted prior to backfill. This work was considered and indicated that additional remedial response actions were necessary to advance the IRA to evaluate exposure risks as the driver for consideration of remedial alternatives analysis on a cost to benefit basis to meet regulatory closure objectives. In the interim, under verbal approvals granted, on August 25, 2021, a vac-truck was used to remove oily water from the 1 ¼ inch galvanized well (IW-1) set within the release area. The intent of this work was to use of the vac-truck to simulate high-vacuum extraction in the upper portion of the aquifer wherein the water level would be dropped and LNAPL and oily water accumulated. This work had limited success and recovered only 68 gallons of oily water with globules of free phase dyed fuel oil due to the low permeability of the very fine silty sands in the upper portion of the shallow aquifer and size and construction of the driven well. Such work indicated limitations of using the well as part of the remedial alternative consideration of bio-sparging. On August 26, 2021, additional soil testing was conducted to further evaluate the extent and magnitude of soil impacts along the perimeter of the excavation area. A series of seven borings were conducted as part of this supplemental assessment [HB-16 to HB-22]. Field testing indicated no significant impact with TOV concentrations as less than 5 ppmv in the 0-4’ intervals at these locations. Otherwise, composite sidewall (4- 8’) and bottom of hole (8-10’) samples were submitted for EPH/VPH analysis for each of these perimeter locations. This analytical data was pending at the time of the second IRA Status Report filing on September 14, 2021. NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 8 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 IRAS3 Status Update (9/14/21 to 10/29/21) In the current reporting period, the analytical results for the additional soil testing were reported as indicating significant residual soil impacts below and beyond the extent of former soil removal in the 4-8’ bs intervals (10- 14’ bgs) along the southern and eastern perimeter areas [EX-S3, EX-S4, HB-18 and EX-S-1] and from 8-10’ bs (14-16’ bgs) in all other perimeter areas; most notably along the southern and eastern perimeter [HB-18, EX- B-16, HB-19, HB-20 and HB-22]. Analytical results show that residual impacts are significantly greater than the applicable Method 1 – Risk Characterization standards as driving exposure risks, most notably vapor intrusion. These analytical results are summarized on Table 2 and define a new target area for in-situ treatment or aggressive soil removal with the benefit of dewatering remedial options. These targeted areas for soil and groundwater treatment/removal are shown on the Site Plan in Appendix A. The analytical results received on September 9, 2021 were incorporated into site characterization input forms for recommendations for in-situ treatment to MicroBac and Regenesis. These soil testing results and analytical summaries are presented in Appendix E. The soil testing and groundwater results indicate a 30-foot x 20-foot x 2-4-foot (D) area of impact running from the MW-1 monitoring well to the back of the interior wall separating the basement laundry area from living room as targeted for treatment or soil removal to a depth of 10 feet below the basement floor. It is estimated that some 80-90 yards impacted soils are located in this area, and some 3,300 gallons of impacted groundwater within the interstitial pore space in these soils. GSE returned to the property on September 14, 2021 for the Operation, Monitoring and Maintenance (OM&M) inspection and monitoring of the sub-slab soil vapor system and again on September 28-29, 2021 for the OM&M inspection of the system as corresponding to the fourth quarter sampling of monitoring wells, and to repeat indoor air testing in consideration of the CEP. Additional OM&M inspections were made on October 6th, 14th and 29th, and were coordinated around site meetings with contractors and removal of additional impacted groundwater from the IW-1 wellpoint and MW-1, which was replaced with a 2 inch well for this purpose. Through the reporting period, TOV readings within the sub-slab venting system have decreased from 112 ppmv (9/14/21) to 27 ppmv (10/29/21). During the inspection on October 14, 2021, the GAC drum was replaced due to TOV breakthrough. These field-testing results and tracking of OM&M activities are shown in the tracking chart in Appendix B and visually charted below. CLIENT SAMPLE ID HB-16/17-COMP (4-8)HB-16/17-COMP (8-10)HB-18 (4-8)HB-18 (8-10)HB-19-20-COMP (4-8)HB-19-20-COMP (8-10)HB-22 (4-8)HB-22 (8-10) SAMPLING DATE 26-AUG-21 26-AUG-21 26-AUG-21 26-AUG-21 26-AUG-21 26-AUG-21 26-AUG-21 26-AUG-21 LAB SAMPLE ID L2146462-01 L2146462-02 L2146462-03 L2146462-04 L2146462-05 L2146462-06 L2146462-07 L2146462-08 CAS Number S1/G1-14 S1/G2-14 S1/G3-14 Units Q Q Q Q Q Q Q Q General Chemistry Volatile Petroleum Hydrocarbons C5-C8 Aliphatics, Adjusted C5-C8-ALPHA-J 100 100 100 mg/kg 5.57 U 79.3 28.6 U 229 5.93 U 446 5.95 U 90.4 C9-C10 Aromatics C9-C10-ALPHA-UJ 100 100 100 mg/kg 5.57 U 641 72 1240 5.93 U 1870 5.95 U 378 C9-C12 Aliphatics, Adjusted C9-C12-ALPHA-J 1000 1000 1000 mg/kg 5.57 U 614 64 1040 5.93 U 1560 5.95 U 351 Methyl tert butyl ether 1634-04-4 0.1 100 100 mg/kg 0.056 U 0.755 U 0.286 U 0.694 U 0.059 U 0.831 U 0.06 U 0.379 U Naphthalene 91-20-3 4 20 500 mg/kg 0.223 U 9.75 1.15 U 26 0.237 U 40 0.238 U 4.96 Extractable Petroleum Hydrocarbons 2-Methylnaphthalene 91-57-6 0.7 80 300 mg/kg 0.324 U 19.8 U 6.74 U 74.2 U 0.344 U 80.9 U 0.347 U 3.18 Acenaphthene 83-32-9 4 1000 1000 mg/kg 0.324 U 19.8 U 6.74 U 74.2 U 0.344 U 80.9 U 0.347 U 2.01 U Acenaphthylene 208-96-8 1 600 10 mg/kg 0.324 U 19.8 U 6.74 U 74.2 U 0.344 U 80.9 U 0.347 U 2.01 U Benzo(a)anthracene 56-55-3 7 7 7 mg/kg 0.324 U 19.8 U 6.74 U 74.2 U 0.344 U 80.9 U 0.347 U 2.01 U Benzo(a)pyrene 50-32-8 2 2 2 mg/kg 0.324 U 19.8 U 6.74 U 74.2 U 0.344 U 80.9 U 0.347 U 2.01 U Benzo(b)fluoranthene 205-99-2 7 7 7 mg/kg 0.324 U 19.8 U 6.74 U 74.2 U 0.344 U 80.9 U 0.347 U 2.01 U Benzo(k)fluoranthene 207-08-9 70 70 70 mg/kg 0.324 U 19.8 U 6.74 U 74.2 U 0.344 U 80.9 U 0.347 U 2.01 U C11-C22 Aromatics, Adjusted C11-C22-ALPHA-J 1000 1000 1000 mg/kg 6.49 U 1610 1050 7940 6.87 U 13600 6.94 U 1190 C19-C36 Aliphatics C19-C36-ALPHA-UJ 3000 3000 3000 mg/kg 6.49 U 927 462 5020 6.87 U 7460 6.94 U 436 C9-C18 Aliphatics C9-C18-ALPHA-UJ 1000 1000 1000 mg/kg 6.49 U 2190 942 11100 6.87 U 18900 6.94 U 1330 Chrysene 218-01-9 70 70 70 mg/kg 0.324 U 19.8 U 6.74 U 74.2 U 0.344 U 80.9 U 0.347 U 2.01 U Dibenzo(a,h)anthracene 53-70-3 0.7 0.7 0.7 mg/kg 0.324 U 19.8 U 6.74 U 74.2 U 0.344 U 80.9 U 0.347 U 2.01 U Indeno(1,2,3-cd)Pyrene 193-39-5 7 7 7 mg/kg 0.324 U 19.8 U 6.74 U 74.2 U 0.344 U 80.9 U 0.347 U 2.01 U Naphthalene 91-20-3 4 20 500 mg/kg 0.324 U 19.8 U 6.74 U 74.2 U 0.344 U 80.9 U 0.347 U 2.01 U Phenanthrene 85-01-8 10 500 500 mg/kg 0.324 U 19.8 U 6.74 U 74.2 U 0.344 U 80.9 U 0.347 U 2.01 U TABLE 2: ANALYTICAL SUMMARY OF SUPPLEMENTAL SOIL ASSESSMENT (8/26/21) VS METHOD 1 - RISK CHARACTERIZATION STANDARDS MACISAAC IRA RTN4-28586: 24 CHARLES STREET - SOUTH YARMOUTH, MA Q = QUALIFIER, U=NON-DETECT (REPORTING LIMIT CONCENTRATION REPORTED GREY FILL = REPORTING LIMIT CONCENTRATION GREATER THAN METHOD 1 STANDARD, GREEN = REPORTED CONCENTRATIONS GREATER THAN METHOD 1 STANDARD, ORANGE= GREATER THAN S-3 DIRECT CONTACT, YELLOW= GREATER THAN UCL NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 9 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 Analytical results for quarterly groundwater analysis for samples collected on September 29, 2021 again reported the absence of groundwater impacts at all monitoring wells (Non-Detect) with the exception of MW- 1, which has consistently shown groundwater impacts at this upgradient location as attributed to preferential pathway along the silty sand aquiclude at the top of the shallow aquifer. During this sampling round, a 0.01- foot thickness of LNAPL was reported at MW-1 monitoring well wherein an absorbent pad was used to remove standing product ahead of sampling. Notwithstanding, the analytical results at the MW-1 monitoring well reported significantly reduced concentrations of fractional EPH/VPH compounds and target analytes as compared to the previous quarterly testing in July 2021. Only the C9 to C10 aromatic compounds exceeded the GW-1, Method 1 Standard as presented in Table 3 below and as included with the laboratory results in Appendix E. NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 10 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 GW-1 GW-2 GW-3 1/20/21 3/9/21 C9-C18 Aliphatic Hydrocarbons 700 5,000 50,000 3,150 ND 200 5,900 ND 100 C19-C36 Aliphatic Hydrocarbons 14,000 NS 50,000 1,440 ND 200 1,940 ND 100 Unadjusted C11-C22 Aromatics 1,700 236 2,560 C11-C22 Aromatic Hydrocarbons 200 50,000 5,000 1,680 219 2,520 114 Acenaphthene 20 NS 10,000 5 ND 5 0.27 ND 0.4 Acenaphthylene 30 10,000 40 ND 1 ND 1 ND 0.19 ND 0.4 Anthracene 60 NS 30 ND 5 ND 5 ND 0.19 ND 0.4 Benzo(a)anthracene 1 NS 1,000 ND 1 ND 1 ND 0.19 ND 0.4 Benzo(a)pyrene 0.2 NS 500 ND 0.2 ND 0.2 ND 0.09 ND 0.2 Benzo(b)fluoranthene 1 NS 400 ND 1 ND 1 ND 0.19 ND 0.4 Benzo(g,h,i)perylene 50 NS 20 ND 5 ND 5 ND 0.19 ND 0.4 Benzo(k)fluoranthene 1 NS 100 ND 1 ND 1 ND 0.19 ND 0.4 Chrysene 2 NS 70 ND 2 ND 2 ND 0.19 ND 0.4 Dibenzo(a,h)anthracene 0.5 NS 40 ND 0.5 ND 0.5 ND 0.19 ND 0.4 Fluoranthene 90 NS 200 ND 5 ND 5 0.19 ND 0.4 Fluorene 30 NS 40 ND 5 ND 5 1.43 ND 0.4 Indeno(1,2,3-cd)pyrene 0.5 NS 100 ND 0.5 ND 0.5 ND 0.19 ND 0.4 2-Methylnaphthalene 10 2,000 20,000 10 5 16.5 1.43 Naphthalene 140 700 20,000 5.9 12.5 1 16.5 4 Phenanthrene 40 NS 10,000 6.8 ND 1 1 ND 0.4 Pyrene 60 NS 20 ND 5 ND 5 0.66 ND 0.4 C5-C8 Aliphatic Hydrocarbons 300 3,000 50,000 573 420 --108 C9-C12 Aliphatic Hydrocarbons 700 5,000 50,000 2,460 1,430 --1080 C9-C10 Aromatic Hydrocarbons 200 4,000 50,000 1,310 976 --601 Benzene 5 1,000 10,000 67 51.1 --ND 2 Ethylbenzene 700 20,000 5,000 108 112 --44.2 Methyl tertiary-Butyl Ether 70 50,000 50,000 ND 10 ND 10 --ND 3 Naphthalene 140 700 20,000 26 24 --13.2 Toluene 1,000 50,000 40,000 283 289 --39.7 Xylenes (total)10,000 3,000 5,000 507 496 --255 Total Metals Iron NA NA 8,350 Manganese NA NA 263 Dissolved Metals by EPA Methods Iron NA NA 7360 Manganese NA NA 252 BOD ----7 COD ----23 DO ----6.96 Nitrate as N ----0.502 pH ----6.37 Redox Potential ----171 Sulfate (Total)NS NS NS ----8.2 TABLE 3: GROUNDWATER SUMMARY ANALYTICAL RESULTS MW-1 VS METHOD 1 STANDARDS MACISAAC IRA RTN4-28586: 24 CHARLES STREET - SOUTH YARMOUTH, MA All results in micrograms per liter (µg/L). ND= Non-Detect. Lt. Green = Concentrations Exceeding the Method 1 Risk Standards, Dk Green = Elevated Metals Concentrations Exceeding Drinking Water Standards Conventional Chemistry Parameters 7/6/21Sample Date Sample Identification MW-1MCP Method 1 Risk Characterization Standards Extractable Petroleum Hydrocarbons (EPH) by MassDEP Method EPH-04.1.1 Volatile Petroleum Hydrocarbons (VPH) by MassDEP Method VPH 9/29/21 NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 11 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 Indoor air testing results for the basement area samples collected on September 29, 2021 reported significantly lower concentrations of Air-Phase Petroleum Hydrocarbons (APH) relative to previous testing conducted in June 2021 with the benefit of active sub-slab venting and sealing of the basement floor. All such APH concentrations were reported as Non-Detect, or at low level concentrations wherein in all cases, the reported concentrations or reporting limit concentrations, are significantly less than the Residential Threshold Values (RTV). APH concentrations in the first-floor sample were consistent with the previous June 2021 results with the exception of the fact that the concentration of benzene was significantly decreased as considered a confounding compound and the concentration of C5 to C8 aliphatic compounds was significantly increased. It is noted that in the review of this data, that benzene in the most recent sampling of the impacted MW-1 monitoring well was absent and C5 to C8 aliphatic compounds were significantly reduced. This combined with decreasing TOV values in the sub-slab system and the identification of a printing set left in the room where the indoor air sample was collected provide lines of evidence to consider both benzene and the reported C5 to C8 aliphatic compounds as confounding and not representative of vapor intrusion from the subsurface. The analytical results are summarized in Table 4 below, and the complete laboratory report is included in Appendix E. On October 6, 2021, GSE returned to the property to again pump oily water and LNAPL from the IW-1 well point in the release area and from monitoring well MW-1, which had been replaced with a 2 inch casing for this purpose. Again, the use of the vac-truck was limited to the recovery of 200 gallons of oily water with a heavy sheen and globules of free phase dyed fuel oil. This remedial waste was managed at the Tradebe facility in Stoughton as documented on the Oil and Hazardous Waste Manifest included in Appendix C. RISK CHARACTERIZATION AND IMMINENT EVALUATION Soils The end point sampling at the extent of the January 2021 excavation, and most recently in the supplemental soil testing along the perimeter of the area of soil removal, indicates that soil impacts remain above the Method 1 Risk Characterization standards and in some cases above the S-3 Direct Contact Concentrations Location EPC FF Sample ID: Date Sampled: Air-Phase Petroleum Hydrocarbons (APH) by MassDEP Method RL RL RL RL RL RL C5-C8 Aliphatic Hydrocarbons 58 330 2,200 27 15 880 18 140 79 C9-C12 Aliphatic Hydrocarbons 68 220 680 40 ND 10 530 ND 12 33 22.5 C9-C10 Aromatic Hydrocarbons 10 44 14 ND 10 ND 10 14 ND 10 ND 10 5 Benzene 2.3 11 ND 2 ND 2 ND 0.6 ND 2 2.6 1.2 1.9 1,3-Butadiene NS NS ND 2 ND 2 ND 0.5 ND 2 ND 2 ND 0.5 1.25 Ethylbenzene 7.4 7.4 2.3 ND 2 ND 0.9 2.2 ND 2 1.3 1.15 Methyl t-butyl ether (MTBE)39 39 ND 2 ND 2 ND 0.7 ND 2 ND 2 ND 0.7 0.85 Toluene 54 54 8.3 ND 2 ND 0.9 8.6 5.7 8.7 7.2 Naphthalene 0.6 2.7 ND 0.63 ND 0.63 ND 0.26 ND 0.63 ND 0.63 ND 0.26 0.22 m&p-Xylene see Total xylenes 14 14 o-Xylene see Total xylenes 4.1 3.8 Total xylenes 20 28 18 2.1 ND 1.8 17 3.3 6 4.65 First Floor Living Room TABLE 4: INDOOR AIR APH SUMMARY VS RESIDENTIAL THRESHOLD VALUES MACISAAC IRA RTN4-28586: 24 CHARLES STREET - SOUTH YARMOUTH, MA All results are in micrograms per cubic meter (µg/m3). Green Shaded = Concentrations Exceeding RTVL Values, Bold values less than 90th percentile FF-IA3 9/30/2021 FF-IA2 6/24/2021 Residential Threshold Values 4/13/2021 4/13/2021 90th Percentile Residential Typical Indoor Air Concentrations B-IA1 FF-IA1B-IA2 6/24/2021 Basement Utility Room B-IA3 9/30/2021 NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 12 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 considered under Method 2 and the Upper Concentration Limits. Based on the intensity, frequency and accessibility of these soils, which are at least 14 feet below the existing exterior grade, or 8 feet below the footprint of an existing structure, the soil conditions do not represent any Imminent or Substantial Hazards relative to associated ingestion, inhalation or dermal contact exposures at this time. Notwithstanding, these soil concentrations result in the leaching of petroleum hydrocarbons into groundwater as dissolved and free phase concentrations and accumulations and represent the source for the vapor intrusion pathway identified and a potential for substantial release migration to downgradient environmental receptors. Such conditions require additional remedial response actions under the existing IRA to eliminate Significant Risk under the foreseeable future use and activities at the property. Groundwater LNAPL accumulations and groundwater impacts at MW-1 and in the area intermediate and including the previous area of soil removal exist above the Method 1 – Risk Characterizations standards and contribute to the vapor intrusion pathway and potential impact to downgradient receptors as noted. Notwithstanding the fact that the groundwater is likely to qualify as a Non-Potential Drinking Water Source Area for elevated metals and as subject to saltwater intrusion, the presence of LNAPL is a driver for vapor intrusion pathway and the likelihood of substantial release migration. No such downgradient migration is apparent from the most recent testing, and the engineering controls appear to be effective in controlling vapor intrusion and significant inhalation risk. As such, under current conditions, no Imminent or Substantial Hazards are apparent as associated with the ingestion, inhalation or dermal contact exposure to impacted groundwater. Such conditions do, however, require additional remedial response actions under the IRA to eliminate Significant Risk under the foreseeable future use and activities at the property. Vapor Intrusion/Indoor Air The effectiveness of the active system was re-evaluated by repeated APH testing of indoor air on September 29, 2021 as noted above. Notwithstanding the use of lines of evidence to exclude benzene and increased C5 to C8 aliphatic compounds as confounding and as within the 90% of background concentrations measured in homes without a heating oil release, the entirety of the analytical results was evaluated under the Method 3 ShortForms for Imminent Hazard and Significant Risk. Such forms were peer reviewed by Debbie Listernick, a Risk Assessor with the firm of O’Reilly, Talbot and Okum Engineering in Boston, MA, to qualify findings as presented below. NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 13 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 In the evaluation of the full data set, resulting Excess Lifetime Cancer Risk (ELCR) are less than the 1 x 10-5 and the Hazard Index (HI) does not exceed 1.0 using the one significant figure rule. These ShortForms indicate that there is no Imminent or Substantial Hazard associated with the inhalation of impacted air attributed to vapor intrusion under current conditions. Such conditions do, however, require additional remedial response actions under the IRA to eliminate Significant Risk under the foreseeable future use and activities at the property without reliance on mechanical systems to prevent vapor intrusion at higher concentrations. Resident - Indoor Air: Table RAIH-1 ShortForm Version 10-12 Exposure Point Concentration (EPC)Vlookup Version v0315 Based on Resident Age 1-6 (Cancer and Noncancer) ELCR (all chemicals) =6.69E-07 **Do not insert or delete any rows**HI (all chemicals) =8.92E-01 Click on empty cell below and select OHM using arrow. Oil or EPC Hazardous Material (µg/m 3)ELCRair HQair BENZENE 1.2E+00 6.7E-07 1.2E-01 ALIPHATICS C5 to C8 1.4E+02 7.0E-01 TOLUENE 8.7E+00 1.7E-03 ETHYLBENZENE 1.3E+00 1.4E-04 XYLENES (Mixed Isomers)6.0E+00 1.5E-02 ALIPHATICS C9 to C12 3.3E+01 5.5E-02 Resident - Indoor Air: Table RA-1 ShortForm Version 10-12 Exposure Point Concentration (EPC)Vlookup Versionv0315 Based on Resident Ages 1-31 (Cancer) and 1-8 (Noncancer) ELCR (all chemicals) =4.01E-06 **Do not insert or delete any rows**HI (all chemicals) =1.05E+00 Click on empty cell below and select OHM using arrow. Oil or EPC Hazardous Material (µg/m 3)ELCRair HQair BENZENE 1.2E+00 4.0E-06 1.2E-01 ALIPHATICS C5 to C8 1.4E+02 7.0E-01 TOLUENE 8.7E+00 1.7E-03 ETHYLBENZENE 1.3E+00 1.3E-03 XYLENES (Mixed Isomers)6.0E+00 6.0E-02 ALIPHATICS C9 to C12 3.3E+01 1.7E-01 Resident - Indoor Air: Table RA-1 ShortForm Version 10-12 Exposure Point Concentration (EPC)Vlookup Versionv0315 Based on Resident Ages 1-31 (Cancer) and 1-8 (Noncancer) ELCR (all chemicals) =6.35E-06 **Do not insert or delete any rows**HI (all chemicals) =8.44E-01 Click on empty cell below and select OHM using arrow. Oil or EPC Hazardous Material (µg/m 3)ELCRair HQair BENZENE 1.9E+00 6.4E-06 1.9E-01 ALIPHATICS C5 to C8 7.9E+01 4.0E-01 TOLUENE 7.2E+00 1.4E-03 ETHYLBENZENE 1.2E+00 1.2E-03 XYLENES (Mixed Isomers)4.7E+00 4.7E-02 ALIPHATICS C9 to C12 2.2E+01 1.1E-01 AROMATICS C9 to C10 5.0E+00 1.0E-01 METHYL TERT BUTYL ETHER 8.5E-01 2.8E-04 EPC FF 6/24/21 and 9/30/21 NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 14 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 REVIEW OF REMEDIAL ALTERNATIVES UNDER THE IRA [Refer to Appendix D] MicroBac is a provider of a biological remedial additive that has cultured total petroleum hydrocarbon (TPH) degrading bacteria (M1000H) in conjunction with a nutrient solution (Tri-Phasic 12) to provide biological mineralization of petroleum hydrocarbons in soils and groundwater. Regenesis is the provider of the various remedial additives used for petroleum remediation. Their PetroFix product is a powdered activated carbon that absorbs petroleum hydrocarbons from soil and groundwater and fixes such compounds such that bacteria can feed on the carbon source. This product was considered in addition to the MicroBac as a viable bio- remedial strategy. A second product, RegenOx, as a two-part slow-release oxidant was considered in the aggressive soil removal strategy as a contingency for any remaining soil or groundwater impacts as a polishing agent. Information on these products, site characterization inputs and recommendations are provided in Appendix D. Based on the review of projected costs and the relative advantages and disadvantages of the remedial alternatives presented, the owner wishes to proceed with the physical removal of impacted soils and groundwater through de-watering with contingency for RegenOx wherein at the limit of excavation, RegenOx, Part A would be mixed with bottom of hole soils, and an infiltration system would be constructed for potential application of the RegenOx, Part B activator for chemical oxidation treatment. Such would be accomplished under the existing verbal approvals with the understanding that the addition of the Part B activator solution would require written authorization and would be framed as an IRA Modification as requested herein on the BWSC-105 submittal [Refer to Appendix B]. The dwelling would be shored and temporarily moved off the foundation with occupants temporarily relocated. The clean overburden would be removed and segregated for re-use (approximately 120 yards). Once completed, impacted soils would be excavated for direct loading and transport to Ondrick from 4-10 feet below the basement floor, as some 10-16 feet below grade in the front yard area (approximately 115 yards), facilitated by dewatering. At the extent of the excavation at 2 feet below the groundwater interface, some 2,280 pounds of RegenOx, Part A would be mixed with soils into the bottom of hole area, and an infiltration system of perforated pipe in double-washed stone would be constructed within the excavation to stabilize the open hole pending the receipt of analytical results for endpoint soil samples collected. Based on these results meeting the applicable Method 1 standards or otherwise under Method 3 considerations, the decision for the application of the RegenOx, Part B activator would be made as based on prior written approval expressly requested under this IRA Status Report with IRA Modification. Some 440 pounds of RegenOx, Part B would be mixed with 600-800 gallons and water and applied to the bottom of hole area through the infiltration system or otherwise over the washed stone as based on conditions on the ground at the time of such decision. PHASE I INITIAL SITE INVESTIGATION General Disposal Site Information The subject property is a 0.79-acre parcel of land at 24 Charles Street in South Yarmouth, Massachusetts, owned by MacIsaac Amy Trustee/Amy MacIsaac Rev Trust, and currently used as a primary residence. The Town of Yarmouth identifies the property as Parcel ID 70-113-10256 as some 1,500 feet north of the Bass River Bridge in South Yarmouth at the West Dennis Town line. According to the Town of Yarmouth Assessor’s database, the property is improved upon by a single-story, single-family residence, with a living area of 1,928 square-feet, constructed in 1945. The dwelling has a garage with living space upstairs and a walkout basement. The improvements include a wooden deck, landscaped areas, and a gravel driveway. NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 15 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 According to the 2018 USGS topographic map (Dennis, Massachusetts quadrangle), the property is situated approximately 15 feet above the mean sea level on the western portion (front of the property); and slopes down into the 100-year flood zone as waterfront property abutting the Bass River tidal estuary. The subject residential property is surrounded by similar high density residential properties to the north, west, and south. High density commercial development is to the south along Route 28 as a State Highway and transportation corridor. The subject property and the surrounding properties are all serviced by an extensive municipal water system with no potable wells within 500 feet of the Disposal Site, and neither the subject property nor Disposal Site fall within any designated Zone II – Wellhead Protection area or Zone A of any surface water reservoir. There is no municipal sewering in the area and the subject and abutting properties are on private septic systems. A stormwater drain is located along the southern property boundary pursuant to an easement agreement with the Town of Yarmouth, and the outfall is located on the subject property. Based on the Mass GIS Priority Resource mapping overlay and Phase I Site Assessment Map, the property categorically falls within the Cape Cod Sole Source Aquifer, and as such the GW-1, Method 1 – Risk Characterization drinking water standards would apply [Refer to Figure 2 – Appendix A]. These standards for drinking water ingestion exposure are overstated in the area of the subject property as a high-density residential area abutting a tidal estuary wherein the density of development and potential source of pollutants from private sewage discharge and threat of salt water intrusion preclude the development of a public water supply. Notwithstanding further considerations under the provisions of 310 CMR 40.0932(5), the GW-1 standards are considered under the review of additional remedial response measures under the IRA to absolve significant exposure risks to human and environmental receptors identified. Additionally, based on the depth to groundwater at approximately 8-9 feet below grade in the area of the release and footprint of the occupied residential dwelling, the GW-2 and GW-3 Method 1 – Risk Characterization standards are considered in the evaluation of Significant Risk. Based on soil impacts within the release area being below a permanent structure or at depths greater than 4 feet below the existing grade, the S-2 and S-3/GW-`1, GW-2 and GW-3 soil criteria are considered under existing conditions. The S-1/GW-1, GW-2 and GW-3 criteria are further considered under the foreseeable future use and activities at the subject property. Disposal Site Map The Disposal Site, as the subject of RTN 4-28586, is defined by those areas significantly impacted by the fuel oil release and include a portion of the subject property at 24 Charles Street in South Yarmouth, MA. The Disposal Site covers an approximate 30 foot wide x 30 foot long area under the central portion of the dwelling and extends into the front yard and driveway area in the vicinity of the front entrance and location of monitoring well MW-1. This approximate 900 square foot area is depicted on the Site Plan in Appendix A. NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 16 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 Disposal Site History According to the Town of Yarmouth Assessors records, the subject property was constructed in 1945 and has been in residential use since that time. The current Trust was established in April 2020, and the property was previously in the Lockhart family since 1985. There is no known prior use of the property prior to 1945. Release History The Disposal Site is the subject of RTN 4-28586, where an estimated 200+ gallons of No. 2 fuel oil was released to soils and groundwater underlying the dwelling in or around November 6, 2020. Notification of the release was made on November 11, 2019 following subsurface investigations conducted by GSE confirming such impacts to the environment. Verbal IRA approvals have been granted for the removal of up to 200 yards of impacted soils, the evacuation/recovery of up to 2,500 gallons of LNAPL and oily water, and the operations, maintenance and monitoring of an active sub-slab venting system. Response actions taken to address the release have included environmental assessment, the removal of some 17 yards of impacted soils and 300 gallons of LNAPL and oily water. These response actions are documented in the Immediate Response Action Plan (1/6/20), Immediate Action Status Report #1 (3/11/20) and Immediate Response Action Status Report #2 (9/14/20) with accompanying Transmittal forms, filed with the MassDEP and part of the public record. Oil and/or Hazardous Material Use and Storage History No. 2 fuel oil has historically been stored at the subject property for heating purposes. A single-walled, 275- gallon AST was located in the basement of the dwelling prior to the subject release in November 2020. Subsequent to soil removal in January 2021, the property was converted to natural gas. Small quantities of fuel, paints and cleaning supplies are stored and used at the property as typical of residential use. Otherwise, there has been no use or storage of any significant quantities of oil and/or hazardous material (OHM). Waste Management History Typical household solid waste (trash/garbage) is generated at the property as periodically removed and taken to the local municipal transfer station for licensed management or disposal. Sanitary waste from the residential dwelling is managed with a private subsurface sewage disposal system located northwest of the subject building. As part of the remedial response actions undertaken under RTN 4-28586, remedial waste generated has been managed at licensed facilities as documented on Bill of Ladings or Uniform Hazardous Waste Manifests. Environmental Permits and Compliance History Remedial response actions under the Immediate Response Action conducted under verbal approval granted by the MassDEP. These approvals are documented in various BWSC-101 and BWSC-102 forms issued between November 11, 2020 and August 5, 2021. The subject property falls within the 100 foot buffer zone to a Coastal Bank and as such is subject to jurisdiction under the Wetlands Protection Act. Initial response actions were reported to the Yarmouth Conservation Department and work initially proceeded under what appears to have been an understanding that such work was covered under the existing Order of Conditions for SE83-2253 issued on January 19, 2021. On Successor LSP engagement, the Yarmouth Conservation Administrator was contacted to confirm such understanding and advised that an Emergency Certification would be issued to cover NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 17 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 previous work but that moving forward with work beyond environmental testing, a Modification to the Notice of Intent specifically for future soil removal would be required within 60 days of the September 8, 2021 granting of the Emergency Certification. At the time of this filing, the NOI Modification is being prepared for filing, public hearing and approval in advance of the start of the planned IRA Modification with contingency for remedial additive use and chemical oxidation treatment of residuals. These events document environmental permitting and compliance history. The filing of this Phase I Initial Site Investigation and Tier 1 Classification with IRA Status Report, represents a return to compliance in pursuit of a Permanent Solution by way of IRA Modification, as outlined herein. Site Hydrological Characteristics Environmental assessment activities performed at the Site over the past twelve months, have included at least seven (7) test borings and twenty-two (22) hand borings for soil sampling and subsurface characterization, and the installation and testing of seven (7) monitoring wells. Surficial soils at the subject property consist of primarily of glacial outwash sands typical of Harwich Outwash Plain deposits. Site specific geology shows that these unconsolidated sands are interbedded with silts and clays as likely under the influence of more recent deposits along the Bass River. These low permeability silty members are present at the subject property and make up the upper portion of the shallow aquifer at some 14 feet below grade at the front of the house and at less than 8 feet below grade from the basement floor. The differential in porosities and permeability of these soils, and apparent dip of bedding to the west, have influenced the migration of oil from under the house towards MW-1 in an upgradient location. Groundwater gauging was conducted during site visits made by GSE throughout the IRA. Well gauging was used to compute site-specific groundwater flow direction as tidally influenced and ranging from a north- northeasterly to easterly direction as shown on the Site Plan in Appendix A. The resulting solute pathway is towards Bass River approximately 225 feet to the east. Based on the measured shallow hydraulic gradient between MW-1 and MW-3 (7/6/21: 0.0071 ft/ft), and estimated hydraulic conductivity of the fine to very fine silty sands in the upper aquifer as 25 ft/day with 20% porosity, a groundwater flow velocity of 0.5 ft/day is estimated with a 10% retardation considered. As such, the time of travel to intermediate downgradient wells is estimated as 60-80 days. As such, groundwater sampling after January 2021 (3/9/21, 7/6/21 and 9/29/21) would be representative of dissolved phase, downgradient groundwater impacts associated with the November 2020 release. No such downgradient impacts have been reported outside the area of the release as again attributed to the silty nature of the silty sands in the upper aquifer. Nature and Extent of Contamination Significant residual soil impacts remain below and at the perimeter of the previous excavation within a 30 foot x 30 foot area as appearing to be restricted in soils some 4-10 feet below the basement floor as corresponding to the seasonally adjusted groundwater interface. Such soil impacts and LNAPL accumulations have resulted in dissolved phase groundwater impacts as noted within a slightly larger footprint from within the central portion of dwelling and extending westerly by preferential travel to the front entrance exterior area in the vicinity of monitoring well MW-1. These impacted soils and groundwater, in close proximity to the finished basement floor have resulted in a vapor intrusion migration pathway to the dwelling, which is currently being mitigated by engineering controls and active sub-slab venting. These areas of residual soil and groundwater impact, and vapor exposure pathway are targeted for further remedial response actions under the IRA Modification. NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 18 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 Migration Pathways/Exposure Potential Notwithstanding the fact that impacted soils are mostly isolated under the footprint of the dwelling or of limited accessibility with low frequency and intensity of use below 6 feet and that dissolved phase groundwater impacts appear restricted to the release area in silty soils as not driving any substantial hazard under current conditions, these impacts are the driver for vapor intrusion as a CEP and must be addressed for IRA Completion and in support of a Permanent Solution for closure. Future response actions under the continuing IRA Modification are intended to remove impacted soils and groundwater and eliminate the CEP to document a finding of No Significant Risk for the foreseeable future to support a Permanent Solution without conditions as the expressed objective of the owner. EVALUATION OF NEED FOR IRA/PHASE II SCOPE OF WORK An Immediate Response Action is already in place and will continue through the filing of this Phase I Initial Site Investigation and Tier 1 Classification wherein a CEP is present. The continuation of the IRA will be used to remove additional impacted soils and groundwater with contingency for additional chemical oxidation treatment if deemed necessary as driven by significant exposure risk to identified human and environmental receptors. Such will support a finding of No Significant Risk as technical justification for an IRA Completion and Permanent Solution Statement. The continuation of the IRA under Modification to include the contingency for chemical oxidation treatment using the RegenOx remedial additive is at this time considered the Phase II Scope of Work. The design, permitting and approval of such work is expected to take place within 30-days of this filing. Monthly inspections for the operation, maintenance and monitoring of the sub-slab venting system will continue with measurement of TOV influent and effluent. The off-gas GAC treatment will be maintained throughout operation and the GAC filter changed once significant breakthrough is noted (>20% of influent concentration) and the spent treatment filters recycled for re-use or otherwise managed as remedial waste. Quarterly sampling of monitoring wells for EPH/VPH analysis will continue through the planned IRA Modification as will quarterly indoor air testing for APH as long as the building remains occupied. Additionally, baseline water quality testing (iron, sulfate, sodium, pH, ORC, conductivity and DO) will be repeated in the upgradient MW-6 monitoring well and downgradient MW-3, MW-4 and MW-7 monitoring wells and repeated monthly following RegenOx, Part B activator use. Indoor air testing or sub-slab soil vapor testing will be repeated prior to re-occupancy. A Bill of Lading will be prepared and approved by the receiving facility in advance of soil removal for direct loading, transportation and recycling of impacted soil. Hazardous Waste Manifests will be used otherwise for transport and recycling of impacted water and LNAPL from de-watering operations. Endpoint soil samples will be collected from discrete sidewall and bottom of hole areas for EPH/VPH analysis with target analytes. PHASE I COMPLETION STATEMENT The Phase I Investigation has been completed in accordance with the provisions of 310 CMR 40.0480 and a Completion Statement is made herein, in accordance with 310 CMR 40.0484. The Phase I Investigation has been used to qualify the source of fuel oil contamination and to qualify the extent and magnitude of soil and groundwater impacts as limited to the areas of remedial response actions under the IRA. Environmental assessment activities performed have been used to characterize hydrogeologic conditions, establish potential NOVEMBER 8, 2021 MACISAAC: 24 CHARLES STREET – SO YARMOUTH/MCSS-2021-0001 PAGE 19 OF 19 PHASE I/TIER CLASSIFICATION: RTN 4-28586 GREEN SEAL ENVIRONMENTAL | 114 STATE ROAD, BUILDING B, SAGAMORE BEACH, MA 02562 | T: 508-888-6034 migration pathways and review critical exposures for the discrete area of residual soil and groundwater impacts remaining. Such information serves as the basis of the Tier 1 Classification for the Site. Due to the fact that vapor intrusion and unmitigated impact to indoor air, as a CEP, potentially represents a long-term significant exposure risk, the Site is categorically defined as a Tier 1 Site, pursuant to 310 CMR 40.0520(2) (a). CONCLUSIONS The analytical data for soil, groundwater and indoor air testing conducted to date have been evaluated wherein no Imminent or Substantial Hazards are opined under current conditions and temporary engineering controls. Notwithstanding, additional remedial response actions are required to support a condition of No Significant Risk for all potential exposures in the foreseeable future to support regulatory closure and filing of an IRA Completion and Permanent Solution Statement wherein a CEP exists. Additional response actions presented herein for the removal of additional soil and impacted groundwater will be conducted under verbal approvals previously granted. The contingency for remedial additive use for chemical oxidation treatment of any residuals however considered an IRA Modification and does expressly need written approval as now being sought to proceed. Future environmental assessment/monitoring activities will dictate the need for any additional remedial measures to be represented in future IRA Status reports or under the Comprehensive Response Actions statutory timelines to follow. The findings of this investigation, as represented herein, set forth the rationale and technical justification for the Phase I Completion Statement and Tier I Classification established by the certifications made on the attached Transmittal Forms. The LSP opinions are based upon available data and regulations in effect at the time of this reporting. If you have any questions, or need additional information, please contact us directly at your earliest convenience. Sincerely, GREEN SEAL ENVIRONMENTAL, LLC ____________________________ __________________________ David C. Bennett, LSP Victoria Costa, Project Manager Technical Advisor Manager of Environmental Services Encl: Supporting Documentation [Appendices A-G] Cc: Amy MacIsaac, Trustee (Owner/PRP) Robert Whritenour, Town Administrator - Town of Yarmouth, rwhritenour@yarmouth.ma.us 1 Chief Philip Simonian, Yarmouth Fire Department, psimonian@yarmouth.ma.us1 Carl Lawson, Inspector – Yarmouth Health Department, lawson@yarmouth.ma.us1 Kelly Grant, Administrator – Yarmouth Conservation Department, kgrant@yarmouth.ma.us1 1 As part of Public Notice requirements, the report Title Page, Narrative, Index, Transmittal forms and Site Plan are included, pursuant to paperwork reduction policy. The full report is available as public record on the MassDEP website database at https://eeaonline.eea.state.ma.us/portal#!/search/wastesite or, upon written request to GSE, full copy (electronic or paper) will be provided.