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HomeMy WebLinkAboutExh.28_DOE_NFA_Opinon_Letter_Environmental_CovenantSTATE OF WASHINGTON DEPARTMENT OF ECOLOGY Northwest Regional Office• 3190 160th Ave SE• Bellevue, WA 98008-5452 • 425-649-7000 711 for Washington Relay Service• Persons with a speech disability can calf 877-833-6341 October 31, 2019 Jimmy Blais Merlino Properties 5050 First Avenue South, Suite 102 Seattle, WA 98134 Re: No Further Action at the following Site: •Site Name: Stoneway Concrete Renton •Site Address: 1915 Maple Valley Hwy, Renton, WA 98055 •Facility/Site No.: 62244377 •VCP Project No.: NWl 702 •Cleanup Site No.: 2121 Dear Jimmy Blais: The Washington State Department of Ecology (Ecology) received your request for an opinion on your independent cleanup of the Stoneway Concrete Renton facility (Site). This letter provides our opinion. We are providing this opinion under the authority of the Model Toxics Control Act (MTCA), Chapter 70.105D RCW. Issue Presented and Opinion Is further remedial action necessary to clean up contamination at the Site? NO. Ecology has determined that no further remedial action is necessary to clean up contamination at the Site. This opinion is dependent on the continued performance and effectiveness of t�e post-cleanup controls and monitoring specified below. This opinion is based on an analysis of whether the remedial action meets the substantive require­ ments ofMTCA, Chapter 70.105D RCW, and its implementing regulations, Chapter 173-340 WAC ( collectively "substantive requirements of MTCA"). The analysis is provided below. EXHIBIT 28 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Jimmy Blais October 31, 2019 Page 2 Description of the Site This opinion applies only to the Site described below. The Site is defined by the nature and extent of contamination associated with the following releases:  Gasoline-, diesel-, and oil-range petroleum hydrocarbons (TPH-G, TPH-D, and TPH-O), and formaldehyde into Soil.  Formaldehyde, arsenic, and highly alkaline pH into Ground Water. Enclosure A includes a detailed description and diagram of the Site, as currently known to Ecology. Please note a parcel of real property can be affected by multiple sites. At this time, we have no information that the parcel(s) associated with this Site are affected by other sites. Basis for the Opinion This opinion is based on the information contained in the documents listed in Enclosure B. Those documents are kept in the Central Files of the Northwest Regional Office of Ecology (NWRO) for review by appointment only. You can make an appointment by completing a Request for Public Record form (https://www.ecology.wa.gov/About-us/Accountability- transparency/Public-records-requests) and emailing it to PublicRecordsOfficer@ecy.wa.gov, or contacting the Public Records Officer at 360-407-6040. A number of these documents are accessible in electronic form from the Site web page (https://fortress.wa.gov/ecy/gsp/Sitepage.aspx?csid=2121). This opinion is void if any of the information contained in those documents is materially false or misleading. Analysis of the Cleanup Ecology has concluded that no further remedial action is necessary to clean up contamination at the Site. That conclusion is based on the following analysis: 1. Characterization of the Site. Ecology has determined your characterization of the Site is sufficient to establish cleanup standards and select a cleanup action. The Site is described above and in Enclosure A. The lateral and vertical extent of soil and ground water impacted by contaminant releases at the Site have been adequately defined by completion of Site investigations conducted DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Jimmy Blais October 31, 2019 Page 3 from September 1998 through July 2017. Also, the additional analysis provided in the March 7, 2018 “Request for Written Opinion, Focused Feasibility Study and Disproportionate Cost Analysis” addressed the Site characterization data gaps cited in the August 31, 2017 “Further Action Opinion Letter” from Ecology. Site data has been entered into Ecology’s electronic Environmental Information Management (EIM) database. 2. Establishment of cleanup standards. Soil Cleanup Levels: The proposed future use of the Site (residential) does not meet the MTCA definition of an industrial property; therefore, soil cleanup levels suitable for unrestricted land use are appropriate. Soil cleanup levels based on protection of ground water are appropriate. The MTCA Method A cleanup levels (TPH-G, TPH-D, and TPH- O) and Method B cleanup levels (formaldehyde) are considered appropriate for soil at the Site and are protective of human health and the environment. Soil cleanup levels protective of terrestrial ecological receptors are not necessary because the Site meets the Terrestrial Ecological Evaluation (TEE) exclusion criteria (MTCA WAC 173-340-7491). The results of the TEE Evaluation Form worksheet indicated that a TEE exclusion is applicable and that protective cleanup levels based on TEE factors are not required for this Site. Point of Compliance: For soil cleanup levels based on the protection of ground water, the point of compliance is defined as Site-wide throughout the soil profile and may extend below the water table. This is the appropriate point of compliance for the Site. Soil Vapor Formaldehyde in soil vapor was evaluated as a potential vapor intrusion (VI) issue, based on detections of this chemical in soil vapor samples conducted at the Site in 2016. This soil vapor sampling occurred after completion of the on-site removal and in-situ treatment of formaldehyde-contaminated soil in 2010 (see Enclosure A), after confirmation soil and ground water sampling showed concentrations below the Method B cleanup levels. Formaldehyde does not have soil or ground water VI screening levels in the current Ecology VI guidance. Based on this information and data, soil vapor was eliminated as a contaminated media for this Site. DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Jimmy Blais October 31, 2019 Page 4 Ground Water Cleanup Levels: MTCA Method A cleanup levels for arsenic and formaldehyde are the applicable ground water cleanup levels for this Site. A ground water cleanup level for pH does not exist; however, the maximum reported pH value in Site ground water (12.54) was above the characteristic dangerous waste threshold of 12.5; therefore, pH is considered to be a water quality parameter of concern at the Site. Point of Compliance: Ecology has determined the conditional point of compliance proposed for ground water at the Site (western Property boundary) is appropriate for the Site, given the following:  Data documenting a consistent ground water flow direction away from the Cedar River to the northwest has been provided to Ecology, and  It is not practicable to meet the cleanup level for arsenic and an acceptable concentration of pH in ground water throughout the Site within a reasonable restoration time frame, per WAC 173-340(8)(c), due to presence of high pH soils in inaccessible Site areas. 3. Selection of cleanup action. Ecology has determined the cleanup action you proposed for the Site meets the substantive requirements of MTCA. The cleanup meets the minimum cleanup requirements and does not exacerbate conditions or preclude reasonable cleanup alternatives elsewhere at the Site. 4. Cleanup. Ecology has determined the cleanup you performed meets the applicable Site cleanup standards within the Property. The following cleanup actions were completed on the Site (see Enclosure A for details and locations):  Removal and off-Site disposal of 200 cubic yards of high pH soil from the former small settling pond in the southwest corner of the Site (Work Area 1).  Removal and off-Site disposal of 2,200 cubic yards of high pH soil from the large settling ponds adjacent to the Cedar River (Work Area 2).  Removal and off-Site disposal of 190 cubic yards of oil-contaminated soil in an area of shallow soil impacts east of the large settling ponds (Work Area 3). DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Jimmy Blais October 31, 2019 Page 5  Removal and on-Site bioremediation of 21,000 cubic yards of formaldehyde- contaminated soil in the central area of the Site (Work Area 4).  Removal and off-Site disposal of a 600-gallon heating oil underground storage tank and petroleum-contaminated soil (300 cubic yards) and ground water (3,000 gallons), in the northeast area of the Site (Work Area 5). This determination is dependent on the continued performance and effectiveness of the post-cleanup controls and monitoring specified below. Post-Cleanup Controls and Monitoring Post-cleanup controls and monitoring are remedial actions performed after the cleanup to maintain compliance with cleanup standards. This opinion is dependent on the continued performance and effectiveness of the following: 1. Compliance with institutional controls. Institutional controls prohibit or limit activities that may interfere with the integrity of engineered controls or result in exposure to hazardous substances. The following institutional controls are necessary at the Site:  Containment of Soil and Ground Water. Contaminated soil and ground water beneath ground surface at the Site is isolated from direct contact with potential receptors by approximately 15 feet of uncontaminated soil. Existing or future buildings shall not be constructed or altered in any manner that would expose contaminated soil or ground water, result in a release of contaminants, or create a new exposure pathway, without prior written approval of Ecology.  Groundwater Use. The groundwater beneath the Property shall not be extracted for any purpose other than investigation, monitoring, or remediation performed in accordance with requirements imposed by Ecology for the Site. Drilling of a well for any water supply purpose on or beneath the Site is strictly prohibited.  Restrictions on Stormwater Infiltration. Construction of stormwater facilities that are designed to infiltrate to groundwater, or that present the potential for leakage to groundwater, are prohibited within the area of the Site where residual contaminants in soil and groundwater are present and could be mobilized. DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Jimmy Blais October 31, 2019 Page 6 To implement these controls, an Environmental Covenant has been recorded on the following parcel of real property in King County (Recording Number 20190716000692):  Tax Parcel 172305-9026 Ecology signed the recorded Covenant as Grantee. A copy of the Covenant is included in Enclosure C to this opinion letter. Exhibit E of this Covenant is an Operation, Maintenance, and Contingency that was approved by Ecology. 2. Performance of confirmational monitoring. Confirmational ground water monitoring is necessary at the Site to confirm the long-term effectiveness of the cleanup. The monitoring data will be used by Ecology during periodic reviews of post-cleanup conditions. This plan was approved by Ecology and is Exhibit D to the Covenant, which is included in Enclosure C to this opinion letter. Periodic Review of Post-Cleanup Conditions Ecology will conduct periodic reviews of post-cleanup conditions at the Site to ensure that they remain protective of human health and the environment. If Ecology determines, based on a periodic review, that further remedial action is necessary at the Site, then Ecology will withdraw this opinion. Listing of the Site Based on this opinion, Ecology will remove the Site from our Confirmed and Suspected Contaminated Sites List. Limitations of the Opinion 1. Opinion does not settle liability with the state. Liable persons are strictly liable, jointly and severally, for all remedial action costs and for all natural resource damages resulting from the release or releases of hazardous substances at the Site. This opinion does not:  Resolve or alter a person’s liability to the state.  Protect liable persons from contribution claims by third parties. DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Jimmy Blais October 31, 2019 Page 7 To settle liability with the state and obtain protection from contribution claims, a person must enter into a consent decree with Ecology under RCW 70.105D.040(4). 2. Opinion does not constitute a determination of substantial equivalence. To recover remedial action costs from other liable persons under MTCA, one must demonstrate that the action is the substantial equivalent of an Ecology-conducted or Ecology-supervised action. This opinion does not determine whether the action you performed is substantially equivalent. Courts make that determination. See RCW 70.105D.080 and WAC 173-340-545. 3. State is immune from liability. The state, Ecology, and its officers and employees are immune from all liability, and no cause of action of any nature may arise from any act or omission in providing this opinion. See RCW 70.105D.030(1)(i). Termination of Agreement Thank you for cleaning up the Site under the Voluntary Cleanup Program (VCP). This opinion terminates the VCP Agreement governing this project (#NW1702). For more information about the VCP and the cleanup process, please visit our web site: www. ecy.wa.gov/programs/tcp/vcp/vcpmain.htm. If you have any questions about this opinion or the termination of the Agreement, please contact me by phone at 425-649-7257 or e-mail at michael.warfel@ecy.wa.gov. Sincerely, Michael R. Warfel, VCP Site Manager NWRO Toxics Cleanup Program Enclosures (3): A – Description and Diagrams of the Site B – Basis for the Opinion: List of Documents C – Environmental Covenant for Institutional Controls DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Jimmy Blais October 31, 2019 Page 8 cc: Riley Conkin, Farallon Consulting LLC (via email) Lyndsay Gordon, VCP Financial Manager (via email) Sonia Fernández, VCP Coordinator (via email) City of Renton (via email) Jennifer Henning, Planning Director Gregg Zimmerman, Public Works Administrator Chip Vincent, CED Administrator Vanessa Dolbee, Current Planning Manager Brianne Bannwarth, Development Engineering Manager Ron Straka, Utility Systems Director Abdoul Gafour, Water Utility Manager Katie Nolan, Civil Engineer III DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Enclosure A Description and Diagrams of the Site DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Site Description This section provides Ecology’s understanding and interpretation of Site conditions, and is the basis for the opinions expressed in the body of this letter. Site: Stoneway Concrete is located on King County parcel 1723059026 (the Property), which occupies 12.54 acres situated between the Cedar River and SE Maple Valley Highway (Figure 1). The Site boundaries generally follow the Property boundaries. Site History and Current Use: Historical records indicate that the Property was developed in the 1930s as Stoneway Dock Company. The facility name changed to Stoneway Sand and Gravel in the 1950s. During the 1950s and 1960s, the Property was reportedly leased by many businesses, including an asphalt manufacturing company. By 1966, the Property was owned and operated by Stoneway Concrete and in 1985 was purchased by Don Merlino. The Property was most recently occupied by a concrete batch plant, along with associated support activities (Figure 2). Operations on the Property ceased prior to October 2002 in order to conform with the City of Renton aquifer protection ordinance, which precludes industrial activities that use, handle, or store hazardous substances in Aquifer Protection Area Zone 1. Sources of Contamination: Petroleum hydrocarbons were detected in soil due to historic surface spillage and historic releases from underground storage tanks that have been removed. Formaldehyde in soil and ground water is attributed to spills of a chemical additive associated with the concrete batch process. Arsenic, detected in ground water above the cleanup level, was not found in soil at concentrations exceeding natural background concentrations. Physiographic Setting: The Site is relatively flat and slopes from an elevation of 50 feet above mean sea level (amsl) adjacent to State Route 169 on the north to 40 feet amsl at the Cedar River on the south. The Cedar River valley is very narrow in the Site vicinity and is bounded on the north and south by steep valley walls that attain elevations of 300 to 400 feet amsl. Surface/Storm Water System: The majority of the Property is currently paved with concrete that is 4 - 12 inches thick. Unpaved areas are located in the eastern and western portions of the Property. Storm sewer control is in place in the upper portion of the Property and the Property has a storm water permit. Storm water in the lower portion of the Property drains to on-site settlement ponds for infiltration. There are no point source discharges to the Cedar River. Ecological Setting: Most of the Property’s river frontage is protected with erosion control features such as riprap, cast-in-place concrete walls, "Ecology" blocks, and a poured concrete veneer over the native soils. Very little of the original low bank frontage remains and there does not appear to be a riparian habitat on the Property. Geology: The Site is underlain by coarse sands and gravels deposited in the valley of the Cedar River. The Cedar River valley is very narrow in the Site vicinity and is bounded by steep-sided DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 valley walls comprised of glacial till overlying bedrock. The surface of the Site has been graded over time and includes varying thicknesses of fill. The sand and gravel alluvium has been observed in borings to a depth of 50 feet below ground surface (bgs), the deepest exploration on the Site. Ground Water: Ground water occurs under unconfined conditions in the sand and gravel alluvium beneath the Site, in the regional, USEPA-designated Sole Source Cedar Valley Aquifer. The City of Renton obtains the majority of the water supply from well fields in this aquifer, located upstream and downstream from the Site. Local well logs indicate that this aquifer extends to depths up to 72 feet bgs near the Site. Depths to ground water at the Site range from 10 to 20 feet bgs. Data from detailed studies of the aquifer by the City of Renton, and monitoring wells on the Site, confirm a consistent northwesterly flow direction across the Site, away from the Cedar River. This reach of the Cedar River loses a significant volume of surface water through the riverbed into the aquifer, resulting in the down-valley ground water gradient to the northwest. Aquifer tests conducted in the City of Renton wellfield (located within 700 feet northwest of the western Property boundary) document that this prevailing ground water flow direction is not measurably affected by pumpage in the well field. Extent of Contamination and Remedial Actions: From 2005 through 2010, numerous remedial actions regarding soil contamination have taken place at the Property (Figure 5), which are summarized as follows:  Work Area 1- Former Small Settling Pond (southwest corner of Property). High pH soil was present in this area. At total of 200 cubic yards was removed to a depth of 6 feet, with the southwest area excavated to 8 feet. Sixteen performance samples indicated pH at limits of excavation (sidewalls and floor) was 6.0-8.0.  Work Area 2 - Large Settling Ponds. The settling ponds are concrete lined and approximately 15 feet deep. Approximately 2,200 cubic yards of high pH soil were removed from within the settling ponds. Excavation was completed when the concrete sidewalls and bottom were exposed. Because the Site was excavated to concrete, no performance samples were collected. A small amount of high pH soil may remain below and around the concrete settling ponds. Removing this material would involve excavating in and adjacent to the Cedar River, which may pose a risk to salmon spawning habitat and erosion of the bulkheads.  Work Area 3 - Shallow Petroleum Impacted Area. COCs for this area were TPHo and TPHd. Impacted soil in this area was excavated to a depth of 4 feet. Approximately 190 cubic yards of TPHo contaminated soil were removed. Twelve performance samples indicated TPHo and TPHd were below cleanup levels (ranging from less than detection limits to 410 mg/kg). DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1  Work Area 4 - Formaldehyde Impacted Area. This area is the largest on the Site and covers a major portion of the central area of the Property. The final size of this area at the completion of soil excavation was 1.4 acres. The depth of excavation was to approximately 11 feet bgs. Approximately 21,000 cubic yards of material were excavated from the area, of which 13,000 cubic yards were bioremediated on-Site and the remainder disposed off-Site. Performance samples were collected and areas over excavated if a performance sample was above the formaldehyde cleanup level. A total of 447 performance samples were collected and analyzed from this area, with 238 samples representing final performance samples. All final performance samples were below the cleanup level.  Work Area 5 - Heating oil UST. A 600-gallon UST was removed from this area. 300 cubic yards were removed from this area (24 feet x 24 feet) to a depth of 23 feet bgs. During the remediation effort, approximately 3,000 gallons of water that accumulated in the pit was removed. Eleven performance samples were collected. Only one of the performance samples was above analytical detection levels, but below the cleanup level. TPHd levels in the water that accumulated in the pit were 320 µg/L, below the ground water cleanup level. Concentrations of COCs in ground water are shown on Figure 5. As mentioned in the text of this opinion letter, the present status of formaldehyde in ground water cannot be assessed, because the laboratory detection limits for the most recent sampling events were greater than the cleanup level of 5 µg/L. Elevated pH has been observed in monitoring well MW-10 since January 2012 (ranging from 11.02 to 12.54). DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Site Diagrams DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Checked By: JR Disc Reference: FARALLON PN: 266-008 SITE LOCATION Copyright:© 2013 National Geographic Society, i-cubed ³SITE VICINITY MAP OLD STONEWAY CONCRETE SITE 1915 SOUTHEAST MAPLE VALLEY HIGHWAY RENTON, WASHINGTON Washington Issaquah | Bellingham | Seattle Oregon Portland | Bend | Baker City California Oakland | Sacramento | IrvineCONSULTING Quality Service for Environmental Solutions | farallonconsulting.com Farallon Date: 4/13/2017Drawn By: pemahiser Document Path: Q:\Projects\266 Gary Merlino\008 Old Stoneway\FIGURE 1_SITE VICINITY MAP.mxd FIGURE 1 REFERENCE: 7.5 MINUTE USGS QUADRANGLE RENTON, WASHINGTON, DATED 2011 02,000 SCALE IN FEET RENTON Enclosure A, Figure 1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Drawn By: pemahiser Checked By: JR Date: 4/13/2017 FIGURE 2 Disc Reference: !< !< !<; !<!<; !< !<; !<; !<MAPLE VALLEY HIGHWAYCEDAR RIVERGFORMER AGGREGATE STORAGE AREA GFORMER AGGREGATE STORAGE AREA GFORMER SETTLING BASINGFORMER SERVICE PIT GFORMER WAREHOUSE G FORMER SCALE G FORMER MAIN OFFICE GFORMER BATCH PLANTGFORMER ADMIXTURE STORAGE GFORMER SETTLING PONDG FORMER TRUCK WASHOUTGFORMER PUMPHOUSE G FORMER AGGREGATE STORAGE GFORMER WELDING AND CARPENTER SHOP G FORMER TRUCK SHOP GFORMER WASTE OIL AST GFORMER OFFICES MW-10 EPI-MW-7 EPI-MW-6 EPI-MW-9EPI-MW-8 EPI-MW-1 MW-41 EPI-MW-5 MW-1 Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community ³SITE PLAN OLD STONEWAY CONCRETE SITE 1915 SOUTHEAST MAPLE VALLEY HIGHWAY RENTON, WASHINGTONCONSULTING Quality Service for Environmental Solutions | farallonconsulting.com Farallon Washington Issaquah | Bellingham | Seattle Oregon Portland | Bend | Baker City California Oakland | Sacramento | Irvine Document Path: Q:\Projects\266 Gary Merlino\008 Old Stoneway\FIGURE 2_SITE PLAN.mxd FARALLON PN: 266-0080200 SCALE IN FEET LEGEND !<MONITORING WELL (INSTALLED BY EPI AND OTHERS) !<;ABANDONED MONITORING WELL APPROXIMATE SITE BOUNDARY HISTORIC SITE FEATURES Enclosure A, Figure 2 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 !<!<!<;!<!<;!<!<;!<;!<CEDAR RIVERGROUNDWATERFLOW DIRECTIONMW-10(NC)EPI-MW-7(30.82)EPI-MW-6EPI-MW-9(29.93)EPI-MW-8EPI-MW-1(28.38)MW-41EPI-MW-5MW-1(28.02)28.0028.0030.5030.0028.5029.0029.5030.5030.0029.0029.5028.50³CONSULTINGChecked By: JRDisc Reference:FIGURE 3GROUNDWATER ELEVATION CONTOURS AND FLOW DIRECTION FOR SEPTEMBER 15, 2016OLD STONEWAY CONCRETE SITE1915 SOUTHEAST MAPLE VALLEY HIGHWAYRENTON, WASHINGTONQuality Service for Environmental Solutions | farallonconsulting.comFarallon060SCALE IN FEETWashingtonIssaquah | Bellingham | SeattleOregonPortland | Bend | Baker CityCaliforniaOakland | Sacramento | IrvineDate: 4/13/2017Drawn By: pemahiserDocument Path: Q:\Projects\266 Gary Merlino\008 Old Stoneway\Figure 3_Contour_pee.mxdFARALLON PN: 266-008LEGENDAPPROXIMATE SITE BOUNDARY!<MONITORING WELL (INSTALLED BY EPI AND OTHERS)!<;ABANDONED MONITORING WELL(28.38)GROUNDWATER ELEVATION (9/15/16) MEASURED IN FEETABOVE MEAN SEA LEVEL RELATIVE TO NORTH AMERICANVERTICAL DATUM 1988 (MONITORING WELL SURVEY DATAPROVIDED BY ENVIRONMENTAL PARTNERS INC.)GROUNDWATER ELEVATION CONTOUR (DASHED WHERE INFERRED)29.50GROUNDWATER FLOW DIRECTION1 " = 3,000 'MAP LOCATOR(NC)GROUNDWATER ELEVATION NOT CALCULATED. MONITORING WELL SURVEY DATA WAS NOT AVAILABLEEnclosure A, Figure 3DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1  & & &!!(& %   &$""!&!!'%##"%   &$""!&#! !""!%   &$""!#!#&  & & & & % "  $ $'%'("   ( "  !#(""#!$#!("                            "!  " !! ""   ""!"   $!!#"# ! !"##(!    "#&(!# " %(&(!#&"#      #                   &$"# '%" %!"'&!"" %!"'" !&!"" %!"'Enclosure A, Figure 4DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 !<!<!<;!<!<;!<!<;!<;!<CEDAR RIVERMW-10EPI-MW-7EPI-MW-6EPI-MW-9EPI-MW-8EPI-MW-1MW-41EPI-MW-5MW-1³CONSULTINGChecked By: JRDisc Reference:FIGURE 4GROUNDWATER ANALYTICAL RESULTSOLD STONEWAY CONCRETE SITE1915 SOUTHEAST MAPLE VALLEY HIGHWAYRENTON, WASHINGTONQuality Service for Environmental Solutions | farallonconsulting.comFarallon080SCALE IN FEETWashingtonIssaquah | Bellingham | SeattleOregonPortland | Bend | Baker CityCaliforniaOakland | Sacramento | IrvineDate: 4/13/2017Drawn By: shaynesDocument Path: Q:\Projects\266 Gary Merlino\008 Old Stoneway\Figure 4_gwAnalyticalData_pee.mxdFARALLON PN: 266-008LEGENDAPPROXIMATE SITE BOUNDARY!<MONITORING WELL (INSTALLED BY EPI AND OTHERS)!<;ABANDONED MONITORING WELLNOTES:DISSOLVED ARSENIC AND FORMALDEHYDE UNITS ARE IN MICROGRAMS PER LITER (μg/L) pH AT 25 DEGREES CELSIUS BOLD = DENOTES CONCENTRATIONS THAT EXCEED MODEL TOXICS CONTROL ACT (MTCA) CLEANUP LEVEL. < = DENOTES ANALYTE NOT DETECTED AT OR EXCEEDING THE REPORTED LIMIT LISTED. NA = NOT APPLICABLE6/8/2009 10.827<59/29/2009 11.435.8<512/14/2009 10.347.7<53/3/2010 8.585.7<56/1/2010 11.41 4.9169/14/2010 9.357.3<512/14/2010 9.33 4.8<53/2/2011 8.315.2<51/27/2012 9.405.9NA5/15/2012 8.455.7<610/9/2012 8.529.7<51/17/2013 7.656.5NA4/23/2013 9.05 4.2<57/30/2013 7.707.3NA10/21/2013 8.39 4.7<11/23/2014 7.415.2NA7/14/2014 8.855.6<11/12/2015 8.77 3.7<24/13/2015 7.90 4.367/20/2015 7.595.1<210/13/2015 8.85 4.2<1001/13/2016 7.73 3.9<1009/15/2016 7.75.2<100DATE pHDISSOLVED ARSENICFORMALDEHYDEEPI-MW-79/29/2009 NA6.2<512/14/2009 NA7.7<53/3/2010 NA 4.0<56/1/2010 NA 4.8189/14/2010 NA7.1<51/9/2012 10.2717<51/17/2013 11.946.8NA4/23/2013 11.44 3.8 <57/30/2013 11.365.9NA10/21/2013 11.696.0<11/23/2014 11.4 4.3 NA7/14/2014 11.83 4.1 <11/12/2015 11.02 2.5 <24/13/2015 11.32 2.7 87/20/2015 11.83 3.6<20001/13/2016 12.54 3.1 <1009/15/2016 11.55<100DATE pHDISSOLVED ARSENICFORMALDEHYDEMW-103/18/2009 7.29 <5<56/8/2009 7.13 <5<59/29/2009 7.06 <1612/14/2009 7.74 1.1<53/3/2010 8.04 <1.8<56/1/2010 7.48 <1.8<59/14/2010 7.09 <1.8<512/14/2010 7.8 <1.8<53/2/2011 6.65 <1.8<55/15/2012 6.6 <1.0NA10/9/2012 6.27 1NA4/23/2013 7.36 <1.0<510/21/2013 6.95 <1.0NA1/23/2014 7.16 1.3NA7/14/2014 6.88 <1.0<11/12/2015 6.59 <1.0NA4/13/2015 6.98 1.3<47/20/2015 7.09 <1.0<210/13/2015 6.55 <1.0<1001/13/2015 7.19 <1.0<1009/15/2016 7.4 <3.0<100DISSOLVED ARSENICFORMALDEHYDEMW-1DATE pH3/18/2009 7.28 <5<56/8/2009 6.96 <5<59/29/2009 7.24 1.7<512/14/2009 7.42 1.6<53/3/2010 7.86 2.4<56/1/2010 7.66 <1.8<59/14/2010 7.14 2.1<512/14/2010 7.58 <1.8<53/2/2011 7.11 2.5<55/15/2012 6.94 1.1NA10/9/2012 6.43 1.4NA4/23/2013 7.64 <1.0<510/21/2013 7.1 1.5NA1/23/2014 7.14 1.5NA7/14/2014 7.24 1.6<11/12/2015 7.65 <1.0NA4/13/2015 6.6 <1.0<47/20/2015 6.96 <1.0<210/13/2015 6.52 <1.0<1001/13/2016 7.09 1.3<1009/15/2016 7.3 <3.0<100DISSOLVED ARSENICFORMALDEHYDEEPI-MW-1DATE pH3/18/2009 6.46 <5<56/8/2009 6.31 <5<59/29/2009 6.47 <1<512/14/2009 6.34 <1<53/3/2010 7.72 <1<56/1/2010 6.63 <1.8<59/14/2010 6.75 <1.8<5DATE pHDISSOLVED ARSENICFORMALDEHYDEEPI-MW-53/18/2009 NA NANA6/8/2009 8.18 <5<59/29/2009 8.30 3.8<512/14/2009 8.22 3.9<53/3/2010 8.16 3.9<56/1/2010 8.19 2.8<59/14/2010 7.96 4.4<5DISSOLVED ARSENICFORMALDEHYDEEPI-MW-6DATE pH3/18/2009 NA NANA6/8/2009 8.15 <5<59/29/2009 8.36 3.9512/14/2009 8.58 4.2<53/3/2010 8.25 4.7<56/1/2010 8.93 3.1<59/14/2010 7.98 4.7<5pHDISSOLVED ARSENICFORMALDEHYDEEPI-MW-8DATE6/8/2009 7.987.0<59/29/2009 7.955.7<512/14/2009 8.265.8<53/3/2010 8.006.6<56/1/2010 8.586.459/14/2010 8.126.6<512/14/2010 8.236.3<53/2/2011 7.997.8<51/27/2012 9.256.6NA5/15/2012 7.228.1NA10/9/2012 7.477.6<51/17/2013 8.836.6NA4/23/2013 8.535.9<57/30/2013 8.427.5NA10/21/2013 8.186.6<11/23/2014 7.35.9NA7/14/2014 8.066.0<11/12/2015 8.26 3.9<24/13/2015 6.16 3.9<47/20/2015 7.09 4.2<210/13/2016 7.26 4.2<1001/13/2016 7.24 3.1<1009/15/2016 7.8 4.7<100DATE pHDISSOLVED ARSENICFORMALDEHYDEEPI-MW-93/18/2009 NA NANA6/8/2009 5.87 <5<59/29/2009 6.65 <1<512/14/2009 6.58 <1<53/3/2010 7.77 <1.8<56/1/2010 6.65 <1.8<59/14/2010 7.11 <1.8<5DATE pHDISSOLVED ARSENICFORMALDEHYDEMW-41Enclosure A, Figure 5DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Enclosure B Basis for the Opinion: List of Documents DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 1. July 19, 2018. Site No Further Action Likely Opinion Letter, Stoneway Concrete, 1915 SE Maple Valley Highway, Renton, WA, VCP NW1702. Washington State Department of Ecology. 2. March 7, 2018. Request for Written Opinion, Focused Feasibility Study and Disproportionate Cost Analysis, Old Stoneway Renton Property, 1915 Southeast Maple Valley Highway, Renton, Washington, VCP Project No. NW1702. Farallon Consulting. 3. August 31, 2017. Further Action Opinion Letter, Stoneway Concrete, 1915 SE Maple Valley Highway, Renton, WA, VCP NW1702. Washington State Department of Ecology. 4. April 13, 2017. Cleanup Status and Permanent Cleanup Action, Old Stoneway Renton Property, 1915 Southeast Maple Valley Highway, Renton, WA. Farallon Consulting. 5. August 11, 2015. Cleanup Status, Former Stoneway Concrete Batch Plant, 1915 SE Maple Valley Highway, Renton, Washington. Environmental Partners, Inc. 6. December 29, 2011. Further Action Opinion Letter, Stoneway Concrete, 1915 SE Maple Valley Highway, Renton, WA, VCP NW1702. Washington State Department of Ecology. 7. October 12, 2011. Interim Action Report Volume 1, Former Stoneway Batch Plant, 1915 SE Maple Valley Highway, Renton Washington, WA. Environmental Partners, Inc. 8. May 9, 2011. Further Action Opinion Letter on Interim Action Report, Stoneway Concrete, 1915 SE Maple Valley Highway, Renton, WA, VCP NW1702. Washington State Department of Ecology. 9. February 7, 2011. Interim Action Report, Volumes 1 and 2, Former Stoneway Batch plant, 1915 SE Maple Valley Highway, Renton Washington, WA. Environmental Partners, Inc. 10. April 30, 2009. Opinion on Proposed Cleanup of the following Site: Former Stoneway Batch Plant, 1915 SE Maple Valley Highway, Renton Washington, WA, VCP NW1702. Washington State Department of Ecology. 11. March 9, 2009. Cleanup Action Plan, Stoneway Concrete, 1915 SE Maple Valley Highway, Renton, WA, Environmental Partners, Inc. 12. October 30, 2007. Ex Situ Soil Bioremediation Treatability Study, Stoneway Concrete, 1915 SE Maple Valley Highway, Renton, WA, Environmental Partners, Inc. 13. September 17, 2007. Interim Remedial Action Letter Report, Stoneway Concrete, 1915 SE Maple Valley Highway, Renton, WA, Environmental Partners, Inc. DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 14. May 5, 2006. Remedial Investigation Report, Stoneway Concrete, 1915 SE Maple Valley Highway, Renton, WA, Environmental Partners, Inc. 15. April 17, 2001. Department of Ecology Memorandum from Joanne Polayes to file. Discontinuation of groundwater monitoring for tetrachloroethene at Stoneway Concrete, Renton. 16. September 20, 1998. Final Report, Stoneway Tetrachloroethene (PCE) Assessment Renton, Washington. Pacific Groundwater Group. DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Enclosure C Environmental Covenant for Institutional Controls DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1