RISK ASSESSMENT FORMER UNION OIL SERVICE STATION WITHNELL PROPERTY 2540 PORTLAND ROAD NE SALEM, OREGON

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2 RISK ASSESSMENT FORMER UNION OIL SERVICE STATION WITHNELL PROPERTY 2540 PORTLAND ROAD NE SALEM, OREGON (LUST File No ) Prepared for: Richard and Gayle Withnell 3691 Rivercrest Drive N Keizer, OR Prepared by: PO Box Portland, Oregon Ph: Fax: Project: October 28, 2011

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4 CONTENTS ACRONYMS AND ABBREVIATIONS... iii EXECUTIVE SUMMARY... iv 1.0 INTRODUCTION Site Setting Description and Location Topography Geology Hydrogeologic Setting Surface Water Ground Water Background Summary of Environmental History RESIDUAL IMPACTS Soils Reconnaissance Ground Water Soil Impact Distribution BENEFICIAL USES OF GROUND WATER Zoning and Land Use Water and Sewer Utilities Willamette Aquifer Water Well Inventory Ktec Door to Door Survey HYDROGEOLOGIC CONCEPTUAL MODEL AND LOCALITY OF THE FACILITY RISK ASSESSMENT Constituents of Interest Initial Screening of Constituents of Interest Identification of COPCs in Soil Identification of COPCs in Ground Water EVREN Northwest, Inc. i December 2, 2011

5 CONTENTS 5.3 Conceptual Site Model Media of Concern Land Use and Ground Water Use Identification of Potential Receptors Pathways of Concern Identification of Constituents of Concern Subsurface Soils Ground Water Evaluation of Risk To The Environment DATA GAP ANALYSIS Soils Reconnaissance Ground Water Discussion CONCLUSIONS AND RECOMMENDATIONS LIMITATIONS TABLES (IN TEXT) 3-1 Table of Water Wells, Section 14, T. 7 S., R. 3 W. 5-1 Exposure Pathway Applicability TABLE (BEHIND TABLES TAB) 1 Summary of Analytical Results, Soil 2 Summary of Analytical Results, Ground Water 3 Risk Evaluation of Identified COPCs in Subsurface Soil 4 Risk Evaluation of Identified COPCs in Ground Water FIGURES 1 Site Vicinity Map 2 Site Plan 3 Site Plan with Historical Features 4 Sample Location Diagram 5 Zoning Map 6 Beneficial Use Survey and Locality of the Facility 7 Conceptual Site Model (Human Health) EVREN Northwest, Inc. ii December 2, 2011

6 ACRONYMS AND ABBREVIATIONS bgs BTEX COCs COIs COPCs CSM DRO ENW HHRA LOF mg/kg ODEQ OHSDWP OWRD PAHs RBCs RBDM RRO Succeed TPH µg/l below ground surface benzene, toluene, ethylbenzene and total xylenes constituents of concern constituents of interest constituents of potential concern conceptual site model diesel-range organics EVREN Northwest, Inc. human health risk assessment locality of facility milligrams per Kilogram Oregon Department of Environmental Quality Oregon Health Services Drinking Water Program Oregon Water Resources Department polyaromatic hydrocarbons risk-based concentrations ODEQ s Risk-Based Decision-Making for the Remediation of Petroleum Contaminated Sites guidance document, 2003 revision residual-range organics Succeed Safety & Health Services, Inc. total petroleum hydrocarbons micrograms per Liter EVREN Northwest, Inc. iii December 2, 2011

7 EXECUTIVE SUMMARY At the request of Richard and Gayle Withnell, EVREN Northwest Inc. (ENW) has prepared this human health risk assessment for the property located at 2540 Portland Road NE in Salem, Oregon. Thos risk assessment was conducted in accordance with Oregon Administrative Rules through 0360 and following the Oregon Department of Environmental Quality s (ODEQ s) Risk Based Decision Making for the Remediation of Petroleum Contaminated Sites (RBDM) guidance document, 2003 revision. ODEQ approved the Work Plan for this project on September 26, All previous environmental investigation and cleanup work at the site was performed by other consultants (discussed further in this report). Also note that environmental investigation and remediation is being performed in the northern and central portions of the property by other consultants, under a different contract. This Risk Assessment addresses only the former Union Oil Service Station location in the southernmost portion of the Withnell property. The site is located in a predominantly commercial area of Salem, and is an irregularly shaped tax lot. The site is currently developed with a used car lot in its southern portion, a large office building in its central portion most recently occupied until 2010 by the Oregon Department of Motor Vehicles, and a parking lot in its northern portion. The site is relatively level. However, there is a very gentle topographic grade toward the northwest. Based on previous assessments, the southern portion of the site was developed as follows: With an automotive service station from the mid-1920s through around From 1949 to 1985, the site was also used for trailer sales. o Five underground storage tanks (USTs) were removed prior to the Withnell purchase of the property in From 1988 to 1991 Dick Withnell Used Cars occupied the property. By 1990 an office building with associated asphalt-paved parking lot was developed further north on the site, and was later expanded and occupied by the Oregon Department of Motor Vehicles (DMV) from at least 1995 until Additionally, based on previous assessments by other, the environmental history is summarized as follows: In 1985, Coffey performed a Phase I Environmental Site Assessment on the southern portion of the property and determined that an automotive service station had been located in the southern portion of the property. Four locations were screened with shallow borings and a photoionization meter, which indicated possible impacts from volatile substances at three of the locations. Two soil samples were collected near the highest photoionization meter detection location. However, no petroleum hydrocarbon impacts were detected in the samples. EVREN Northwest, Inc. iv December 2, 2011

8 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment In 2002, petroleum impacts were discovered in the City right-of-way immediately west and south of the site. GeoEngineers was contracted by the City to supervise removal of impacted soils along the utility trench and vaults in that vicinity. Two samples collected contained impacts from petroleum hydrocarbons (gasoline- and residual (oil)-range in the sample to the south, and diesel-range in the sample to the west). However, the diesel detection was flagged by the laboratory to indicate that the chromatogram pattern was not representative of diesel. Gasoline-range impacts were not quantified. In 2009, Ktec Environmental Consulting completed an Investigation for Magnitude and Extent in the southern portion of the property, consisting of a geophysical survey and seven borings. The geophysical survey indicated that there were no remaining underground storage tanks, but did identify several areas of disturbed soils suggestive of backfilled former tank excavations. The seven Ktec borings were sited based on geophysical data and on the former service station s footprint. Gasoline-range hydrocarbons (at up to 5,490 milligrams per kilograms), diesel-range hydrocarbons (at up to 1,120 milligrams per kilograms), and residual (oil)-range hydrocarbons (at up to 3,120 milligrams per kilograms) were detected in soils. Ktec also collected reconnaissance ground water samples from six of the seven borings, and impacts of gasoline-, diesel-, and/or residual (oil)-range hydrocarbon were detected in all six reconnaissance ground water samples. Gasoline-range hydrocarbons were detected at up to 4,050 micrograms per liter, diesel-range hydrocarbons at up to 5,610 micrograms per liter, and residual (oil)-range hydrocarbons at up to 4,910 µg/l. Ktec additionally conducted a beneficial ground water use determination survey to identify uses of ground water in the vicinity of the site. This risk assessment initially screened constituent of interest related to gasoline-, diesel-, and residual (oil)-range hydrocarbons in soil and ground water against the screening-level risk-based concentrations provided by the Oregon Department of Environmental Quality. Gasoline-range hydrocarbons, ethylbenzene, naphthalene, 1,2,4- and 1,3,5- trimethylbenzene, and xylenes were identified as Constituents of Potential Concern for subsurface soil at the site. Gasoline- and diesel-range hydrocarbons, benzene, ethylbenzene, naphthalene, 1,2,4- and 1,3,5-trimethylbenzene, benzo[a]pyene, and benzo[b]fluoranthene were identified as Constituents of Potential Concern in ground water. A conceptual site model was then developed to identify complete exposure pathways to human receptors. The impacted media were subsurface soils and ground water. The human receptors were identified as occupational workers, construction workers, and excavation workers. However, since the zoning of the site does not preclude residential use, residents were also conservatively included in the risk assessment (although future residential use is considered unlikely). The complete exposure pathways were identified as vapor intrusion into interior air, volatilization to exterior air, and, for excavation workers, EVREN Northwest, Inc. v December 2, 2011

9 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment dermal contact, inhalation, and incidental ingestion of both impacted soil and ground water. (Although depth to water-bearing soils is greater than 15 feet at the site, ground water is under head, and ground water is included for dermal contact of an excavation worker to be conservative with this risk assessment.) Petroleum constituent impacts to soil do not present an unacceptable health risk to occupational and excavation workers. However, volatilization of petroleum constituents into residential interior air exceeds risk-based concentrations. Since the site is in commercial corridors along Portland Road NE and Silverton Road, and since the site is bounded by a railroad track, future residential use is considered unlikely and could be restricted with an institutional control. Petroleum constituent impacts to ground water do not present an unacceptable health risk to any human receptors (the drinking water pathway for ground water is considered incomplete since the City provides water to the site and all properties in the vicinity of the site, and future use of shallow ground is unlikely). ENW recommends that the property should receive regulatory closure with deed restrictions (equitable easement and servitude) stipulating: 1) Prohibition of future residential use of the property. However, residential use could be granted in the future if engineering controls were utilized during construction, or remediation were conducted followed by additional investigation and assessment of risk, or a soil vapor assessment could be conducted to further evaluation the vapor intrusion pathway; 2) Prohibition of installation of any water wells for drinking water or other use, and; 3) Adherence to a Contaminated Media Management Plan to be developed for the property. The Contaminated Media Management Plan should stipulate hazardous materials management and disposal procedures, as well as ensure safe working conditions for future site workers. The deed restrictions should remain in effect until future investigation or future remedial actions demonstrate that the above stipulations are no longer required to protect future human receptors at the site. EVREN Northwest, Inc. vi December 2, 2011

10 1.0 INTRODUCTION At the request of Richard and Gayle Withnell, EVREN Northwest Inc. (ENW) has prepared this Human Health Risk Assessment (HHRA) for the property located at 2540 Portland Road NE in Salem, Oregon (subject site; Figure 1). The HHRA was conducted in accordance with Oregon Administrative Rules through 0360 and following the Oregon Department of Environmental Quality s (ODEQ s) Risk Based Decision Making for the Remediation of Petroleum Contaminated Sites (RBDM) guidance document, 2003 revision. ODEQ approved the Work Plan 1 for this project on September 26, Please note that previous environmental investigation and cleanup work at the site has been performed by other consultants (discussed further in this report). 1.1 Site Setting Description and Location The subject site is located in Salem adjacent to the intersection of Portland Road NE and Silverton Road, within the southernmost portion of current Tax Lot 700 (Figure 2). For approximately 17 years, up until approximately 2010, the area has been used as a paved parking lot for a Oregon Department of Motor Vehicles (DMV) field office (situs address 2640 Portland Road NE, located further north on the same tax lot). However, the site is currently occupied by a used automobile retailer. The historical address of the removed Union service station, 2540 Portland Road NE, is no longer assigned to the site but is retained to distinguish it from other investigation and cleanup activities being performed by others in the northern portion of this same tax lot Topography The US Geological Survey Salem 7.5-minute topographic map shows that the site is located at an approximate elevation of 162-feet above mean sea level (Figure 1). The site is relatively level. The map indicates a very gentle north to northwest topographic grade. 1.2 Geology The site is located in the central Willamette Valley of western Oregon. The Willamette Valley is a major physiographic province of western Oregon located between the Coast Range to the west and the Western Cascade Range to the east. Geologic mapping of the this portion of the Willamette Valley shows the site is located on the Older Alluvium of Walker and Duncan (1989) 2 and the alluvium and glacial outburst flood sediment (including 1 ENW, September 26, 2011, Work Plan, Risk Assessment and Corrective Action Plan, Former Union Oil Service Station, Withnell Property, 2540 Portland Road NE, Salem, Oregon. 2 Walker, G.W., and Duncan, R.A., 1989, Geologic map of the Salem 1 o by 2 o Quadrangle, western Oregon: US Geological Survey, Miscellaneous Investigation Series, Map I -1893, 1:250,000. EVREN Northwest, Inc. 1 December 2, 2011

11 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment Willamette Silt) unit of Gannett and Caldwell (1998). 3 These deposits were emplaced by late Pleistocene catastrophic floods (Missoula Floods) that were impounded within the Willamette Basin. The uppermost deposits of this unit are very fine-grained and dominated by silt composed primarily of quartz, feldspar, ferromagnesian minerals, and mica, with 3 varying amounts of clay and fine sand. The fine-grained unit is designated as the Willamette Silt in most geologic studies of the area, including Gannett and Caldwell (1998). Beginning at approximately 18 to 21 feet below ground surface (bgs), the Willamette Silt is underlain by interbedded sandy gravels and gravelly sands, deposited as deltaic deposits of the major drainages that discharge into the Willamette Valley from the Cascade highlands to the east (Gannett and Caldwell, 1998). The unit is greater than 100 feet thick in the vicinity of the subject property, and is underlain by basaltic bedrock, based on the deep wells within the vicinity of the site. During Ktec Environmental Consulting s (Ktec s) January subsurface site investigation, fill soils consisting of gravels, sands, and silty sands were encountered in the upper to intermediate depth portions of many of the borings, which were completed at 20 feet bgs. 1.3 Hydrogeologic Setting Surface Water There are no natural surface water features on the subject site. The nearest surface-water features are the Willamette River, located one mile to the west of the subject property, and Claggett Creek, located one mile northeast of the subject property. No seeps, springs, ponds, creeks, ephemeral drainages, lakes, or flood plains are located in the immediate vicinity of the subject property. Almost the entire property is paved. Storm water discharges to the municipal storm water system Ground Water At below approximately 18 to 21 feet bgs, the site is underlain by interbedded sandy gravels and gravelly sands that correspond to the Willamette Aquifer, as described by Woodward and others (1998) 5. The Willamette Aquifer is a major source of ground water in rural areas for irrigation and for domestic use. According to Ktec, water rose in borings to a static level of between 5 to 7 feet bgs after penetrating the Willamette Aquifer, suggesting confined or semi-confined conditions in the coarse-grained sediments at depth. However, in the native fine-grained sediments below the site, ground water levels appeared to be at approximately 20 feet bgs (one 20-foot 3 Gannett, M.W., and Caldwell, R.R., 1998, Geologic framework of the Willamette Lowland Aquifer System, Oregon and Washington: US Geological Survey, Professional Paper 1424-A, 32 p., maps (1:250,000). 4 Ktec Environmental Consulting, April 12, 2010, Magnitude and extent investigation report former Union Oil automotive refueling facility, 2540 Portland Road NE, Salem, Oregon 97303: Prepared for Richard and Gail Withnell, 37 p., appendices, figures, tables. EVREN Northwest, Inc. 2 December 2, 2011

12 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment boring did not encounter ground water at all). Woodward and others (1998) 5 show ground water flow is to the northwest in the immediate vicinity of the site. 1.4 Background Previous assessments have indicated that the site was an automotive service station from the mid-1920s through around However, the 1936 aerial photograph indicated two dwellings were also located on the site. By 1955 the southernmost home was removed, and the other dwelling had been replaced by a new building. From 1949 to 1985, the site was also used for trailer sales. Five underground storage tanks (USTs) were removed at the subject site immediately prior to the purchase of the property in 1987 by Richard and Gayle Withnell. The site was then cleared in 1987, and from 1988 to 1991 Dick Withnell Used Cars occupied the property. By 1990 an office building with associated asphalt-paved parking lot was developed further north on the site. That building was subsequently expanded and was occupied by the Oregon Department of Motor Vehicles (DMV) from at least 1995 until See Figure 3 (Site Plan with Historical Features), which shows approximate locations of some of these features. It should be noted that a former Shell Station was located in the northern portion of the Withnell Property, and a former Union Oil Bulk Fuel Facility was located on the east side of the Southern Pacific Railroad easement that bounds a portion of the east side of the Withnell Property (see Figure 3). These sites have their own release histories and are not included in the Scope of Work described in this document. They are being addressed by other consultants. 1.5 Summary of Environmental History In 1995, a Level 1 Environmental Site Assessment 6 was conducted, which summarized site story. The DMV was already occupying the central portion of the site. The Level I Assessment documented available information regarding the 5 USTs removed in The report stated 2,000 gallons of dirty water were pumped from the two 4,000-gallon, two 2,000-gallon, and one 500-gallon capacity tanks, with the source of that information attributed to Dick Withnell. After pumping and completing the tank removal, the excavation was backfilled with pit run gravel and covered with asphalt. Documents for the decommissioning project did not mention leakage or impacted soil associated with the tanks. No soil or ground water samples were collected at that time. Coffey and Associates also drilled four vapor probes in the area suspected as being the former location of the underground storage tanks (see Figure 4 for all sampling locations). The samples were collected at one foot bgs by capping PVC pipe in the shallow borings, sealing with silicone cement, and then monitoring with a photoionization detector (PID). 5 Woodward, D.G., Gannett, M.W., and Vaccaro, J.J., 1998, Hydrogeologic framework of the Willamette Lowland Aquifer System, Oregon and Washington: US Geological Survey, Professional Paper 1424-B, 822 p., maps (1:250,000). 6 Coffey & Associates, October 6, 1995, Level One Environmental Site Assessment. EVREN Northwest, Inc. 3 December 2, 2011

13 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment Results of the survey showed PID response of 20 parts per million volatile organic vapors in their Probe VP-3 in the south corner of the property. Probes VP-2 and VP-4 had PID readings of 1 to 10 ppm. Probe VP-1 did not have any PID response. Since this procedure does not meet any current sampling protocols or measurement standards, this data is not used in the risk assessment described in this report. However Coffey also collected two soil samples at a boring labeled on Figure 4 as B-1 Coffey, near the location of VP-3, but reportedly did not have any detectable concentrations of petroleum hydrocarbons (depths not known). Since these samples were collected over 16 years ago, the data is not considered current, and is not used in the risk assessment. In 2002, the City of Salem performed excavation and infrastructural improvements adjacent to the location of the former Union service station (southernmost Withnell property). Petroleum contaminated soil was encountered in their excavation, and GeoEngineers was retained to supervise removal of the impacted soils in the City s right-of-way and to perform soil sampling. A total of 565 tons of petroleum-contaminated soils were removed (the 2002 GeoEngineers letter 7 to the City of Salem indicates that an unspecified portion of the soil tonnage may have been from the Highway Fuel and Kadel Auto Body sites, other locations where removal activities were underway), and seventeen soil samples were collected during and after the removal. Two of the seventeen samples contained impacts of gasoline-, diesel- and residual (oil)-range hydrocarbons (GRO, DRO and RRO, respectively, see Figure 4 and Table 1, following the Tables Tab after the text of this report). Sample DMV-1 was located in the southernmost portion of the property, and Sample was located under the City easement bordering the west side of the property. The report emphasized that the removal and sampling was not intended to be a delineation, but to remove contaminated soil in the utility vault and trench areas where construction activities occurred. The impacted soils in the easement were suspected to be associated with the former Union Service Station. An Indoor Air Quality Evaluation was conducted by Succeed Safety & Health Services, Inc., 8 (Succeed) on behalf of Ktec in March of The only indoor air volatile organics constituents detected above Method TO-15 reporting limits were acetone and isopropyl alcohol. These detections do not appear to be related to the petroleum impacts underlying the subject property, and the lack of other detections indicates that vapor intrusion into the onsite commercial building is not currently an issue. 9 A limited Site Investigation Work Plan was submitted for the site in October 2008 by Ktec. The Work Plan proposed a geophysical survey and the completion of seven Geoprobe borings to a depth of 20 feet. Since ground water was anticipated at 18 feet bgs, the 7 GeoEngineers, Inc., November 11, 2002, Summary of Environmental Services, CDRE Number 57, Withnell Property (Department of Motor Vehicles) 2640 Portland Road Northeast, Salem, Oregon: Letter-Report to the City of Salem, Public Works Department, 2 p., maps, tables. 8 Succeed. March 11, Indoor Air Quality Evaluation. 9 Ktec, LLC., October 8, Limited Site Investigation Work Plan. EVREN Northwest, Inc. 4 December 2, 2011

14 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment borings would allow collection of both soil and reconnaissance ground-water samples to characterize and delineate the impacts present, filling in data not provided by earlier investigations. The Work Plan was approved as written by ODEQ on November 24, In late 2008, Geopotential, Inc. performed a geophysical survey 10 of the entire site, including the former Shell station facility and the former DMV building, both further to the north of the former Union Station, to determine if any USTs remained below the site. No USTs were identified in the former Union station location, although some pipe lines were detected. Most of the anomalies were interpreted to be associated with underground utility lines, pipes, and historical footings/floors. Larger zones of disturbed soils were interpreted as previous tank removal locations. Ktec performed field work on January 14, 2009, as specified in the Work Plan, with ODEQ s project manager onsite. On April 12, 2010, Ktec submitted its Magnitude and Extent 11 Investigation Report to ODEQ for the site, reporting the findings and including a beneficial use survey and risk screening. The report stated that the full magnitude and extent of soil contamination had been determined, with maximum GRO impacts quantified at up to 5,490 milligrams per Kilogram (mg/kg) and DRO impacts at up to 1,120 mg/kg. Volatile organic constituents related to GRO (GRO-related VOCs) and polynuclear aromatic hydrocarbons (PAHs) were also detected by laboratory analyses. GRO impacts were limited to the immediate vicinity of the former Union Oil service station, estimated at approximately 847 cubic yards exceeding Oregon Soil Matrix Cleanup Level II. GRO impacts were detected in Borings B1, B2, B3, B5, and B7, and DRO and RRO impacts were present in Boring B5 and B7, located to the northeast of the former Union service station location. GRO, DRO, and RRO impacts to ground water were also documented; however, the impacts were not completely delineated. Ktec s beneficial use survey indicated there were no beneficial uses of ground water for drinking water within a quarter mile of the subject property, and there was no other beneficial use of ground water within its defined Locality of the Facility (LOF) (consisting of the Withnell property). Based on previous investigations, and supplemented by information provided during their most investigation, Ktec stated that: Soil impacts had been characterized and were limited to the immediate vicinity of the former Union Oil service station; Ground water impacts had not been completely delineated. However, the beneficial use survey indicated that uppermost ground water is not used for drinking water beneficial use within a quarter mile of the site, and that there are no other beneficial uses of ground water within the defined LOF. 10 Geopotential, Inc., February 17 and 18, 2008, Summary Report, Subsurface Mapping Survey to Detect Possible Underground Storage Tanks, DMV Site, 2640 Portland Road NE, Salem, Oregon: Prepared for Ktec, LLC, Report No. 8009, 6 p., maps, appendices. 11 Ktec, LLC. April 12, 2010, Magnitude and Extent Investigation Report, Former Union Oil Automotive Refueling Facility, 2540 Portland Road NE, Salem, OR 97303: Prepared for Richard and Gayle Withnell, 55 p., maps, tables, figures. EVREN Northwest, Inc. 5 December 2, 2011

15 2.0 RESIDUAL IMPACTS 2.1 Soils GeoEngineers and Ktec have assessed soil at the site. Sampling locations are shown on Figure 4. Analytical results are presented in Table 1. GeoEngineers collected their DMV-1 sample at a vault location in the southernmost portion of the property (see Figure 4 for the following discussion). DMV-1, collected at 3.5 feet bgs, contained 610-mg/Kg GRO and 860-mg/Kg RRO. DRO was also detected, but was flagged to indicate that the chromatogram pattern did not match the standard used for DRO, indicating spillover from the adjacent petroleum hydrocarbon ranges. The other impacted sample collected by GeoEngineers was designated , and also was collected at 3.5 feet bgs was collected under the sidewalk bounding the east side of Portland Road, approximately 50 feet northwest of DMV contained 610-mg/Kg DRO, but was flagged by the laboratory because the pattern was not typical of diesel-range hydrocarbons and that GRO detections were not quantified. GeoEngineers collected 15 other samples which did not contain any detectable petroleum hydrocarbon impacts from the immediate vicinity of DMV-1 (indicating a very limited aerial and vertical extent at that location), and north and south of along the sidewalk alignment (indicating a limited north-south extent in that vicinity). Sample DMV-1 was additionally sampled for PCBs, total lead, and VOCs. DMV-1 contained detectable isopropylbenzene (0.15 mg/kg), n-propylbenzene (0.250 mg/kg), 1,2,4- trimethylbenzene (TMB) (0.79 mg/kg), 1,3,5-TMB (0.580 mg/kg), n-butylbenzene (0.370 mg/kg), sec-butylbenzene (0.300 mg/kg), 4-isopropyltoluene (0.280 mg/kg) and naphthalene (0.28 mg/kg); no other VOCs were detected. Lead was detected at 12.5 mg/kg, but no other heavy metals were analyzed. Polychlorinated biphenyls (PCBs) were not detected above the analytical method detection limits. Toxic Characteristic Leaching Procedure (TCLP) analysis showed that cadmium, chromium, and lead were not leachable at detectable levels. Sample was analyzed for VOCs and total lead. Naphthalene (1.20 mg/kg), isopropylbenzene (0.66 mg/kg), n-butylbenzene (1.50 mg/kg), sec-butylbenzene (1.30 mg/kg), and 4-isopropyltoluene (1.80 mg/kg) were detected; all other VOCs were below the analytical method detection limits. Total lead was present at 8.46 mg/kg. The impacted soils identified by GeoEngineers were removed to Riverbend Landfill; however, no confirmation sampling was performed. Ktec s seven borings were sited based on a geophysical survey performed by Pacific Geophysics and based on historical site features. The borings were performed with a Geoprobe rig using hydraulic direct push boring technology. EVREN Northwest, Inc. 7 December 2, 2011

16 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment Petroleum hydrocarbons were detected in soil at concentrations of up to 5,490 mg/kg in the gasoline range (at B7-10), and 1,120 mg/kg in the diesel range (at B5-9). Several of VOCs were detected in soil sample B7-10. GRO exceeding Soil Matrix Level II standards were present at the Boring B1 (5 feet bgs), B3 (5, 10, and 20 feet bgs), B5 (9 feet bgs), and B7 (10, 15, and 16 foot bgs) locations. DRO exceeded Soil Matrix Level II standards in Boring B5 (1,120 mg/kg at 9 foot bgs) only. RRO exceeded Soil Matrix Level II standards at B5 (3,123 mg/kg at 9 feet bgs) only, yet was also detected in Sample B7-10. Table 1 shows all analytical data for the soil samples, including VOC constituents. As indicated above, Ktec estimated the residual soil contamination exceeding DEQ Soil Matrix Cleanup Level II soil cleanup concentrations at 847 cubic yards. The great majority of this residual impacted soil is located in the vicinity of B3 and B7, with a much smaller volume in the B1 vicinity. 2.2 Reconnaissance Ground Water Ktec collected reconnaissance ground water samples from six of their seven soil borings (all borings except Boring B2; see Table 2 and Figure 4). All samples were analyzed by NWTPH-Gx and NWTPH-Dx. Additionally, water samples from B3 and B7 were analyzed by VOCs by EPA 8260B and three water samples (from B3, B4, and B7) were analyzed for PAHs by EPA 8270 SIM. Petroleum hydrocarbons were detected in reconnaissance ground water at concentrations of up to 4,050 µg/l in the gasoline range, 5,610 µg/l in the diesel range, and 4,910 µg/l in the residual (oil) range. GRO was detected in Borings B1, B3, and B7 above 1,000 µg/l but was not detected above the analytical method detection limit in the other borings. The greatest gasoline detections were in Boring B7 (4,050 µg/l) and Boring B3 (3,640 µg/l). DRO was detected in Borings B1, B3, B4, and B7 at greater than 1,000 µg/l, and in B5 at 648 µg/l. The greatest concentration of DRO was in Boring B3, at 5,610 µg/l. DRO was not detected in Boring B6. RRO were detected in all six borings at greater than 1,000 µg/l, with the greatest impacts in Boring B3 (4,910 µg/l). Benzene was detected at concentrations up to 66.5 µg/l; ethylbenzene was detected at up to 146 µg/l. PAHs were detected at low levels in samples collected at B3-H2O and B7-H2O with naphthalene detected at a concentration of 21.6 µg/l (in B7-H2O), and were not detected in the sample collected at B3-H2O. 2.3 Soil Impact Distribution Ktec attempted to contour the analytical data for gasoline at depths of 5, 10, 15 and 20-feet bgs 4. However, since some of the depth intervals in some borings were not analyzed, the iso-concentration maps were only partially complete. The 5-foot iso-concentration map shows the plume is greatest at Boring B3 (within the geophysical anomaly interpreted as being a tank excavation location) and extending southward/southwestward through Boring EVREN Northwest, Inc. 8 December 2, 2011

17 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment B1. Borings B2 and B6 are below Soil Matrix Cleanup Level II for GRO; Borings B4, B5, and B7 were not sampled at or near the 5 foot depth. The 10-foot iso-concentration map shows the soil impacts are centered on Boring B7, located on the west side of the geophysical anomaly identified as a former tank excavation, which is approximately centered on Boring B3. B3 has 151-mg/Kg GRO at 10 feet bgs, and B5 has 89-mg/Kg DRO at 9 feet bgs. Westward attenuation is not indicated on the map. The 15-foot iso-concentration map is very similar to the 10-foot iso-concentration map. GRO concentrations at B7 is 1,290 mg/kg. However, B1, B2, B3, and B6 were not analyzed at 15 feet bgs. B4 and B5 was nondetect at 15 feet bgs. The 20-foot iso-concentration map shows the soil impacts are centered on Boring B3 (241 mg/kg). However, only B6 was sampled at a nearly equivalent depth (B6 was nondetect at 21 feet depth). EVREN Northwest, Inc. 9 December 2, 2011

18 3.0 BENEFICIAL USES OF GROUND WATER Ktec performed a beneficial use survey of the ground water resource in their 2010 report 4, which discusses current and reasonably likely future uses of ground water at and in the vicinity of the Withnell site. Determining the beneficial uses of ground water at or near the site is important to identify potential pathways by which human and ecological receptors may be exposed to site-related contaminants, and is necessary to understand the determination of the LOF, discussed in Section 4.0. The discussion presented here is presented as a supplemental update to the original beneficial use survey. 3.1 Zoning and Land Use ENW accessed the City of Salem s website and confirmed that the Withnell property is zoned Industrial Commercial (IC) and is located in the Pine Street IC Mixed-Use Area of the Portland/Fairgrounds Road Overlay Zone (Figure 5). The Pine Street IC Mixed-Use Area of the Portland/Fairgrounds Road Overlay Zone permits a dwelling unit or guest room for a caretaker or watchman on the premises being cared for or guarded (SRC Chapter 143B.110 (i) (2)). The overlay zone also allows for the following conditional uses if approved by the Planning Administrator: 1) Townhouses, 2) Unlimited number of dwelling units and guest rooms in apartment houses, court apartments, lodging houses, duplexes, condominiums, and mixed-use developments; and 3) Homeless shelters and room and board facilities serving five or fewer persons (SRC 143B.130 (e)(1-3)). However, as pointed out by Ktec, it is very unlikely that the subject property would be developed for these residential uses given its proximity to the railroad tracks and the commercial character of Portland and Silverton roads. Neighboring properties are zoned Public Amusement and Industrial to the east, General Commercial and Industrial to the north, General Commercial to the west, and General Commercial, Public Amusement, and Industrial Commercial to the south. On the adjacent Commercial General zoned properties to the west and south, the following residential uses are permitted: 1) townhouses, 2) apartment houses, condominiums, and court apartments when constructed as a part of a mixed-use development, and 3) planned unit developments (SRC 143B. 080 (j) (1-3)). 3.2 Water and Sewer Utilities Salem provides water to most of its residents and businesses from its watershed on the Santiam River. However, the City does not require connection to the municipal water system and allows water well use within the City limits. EVREN Northwest, Inc. 10 December 2, 2011

19 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment The City maintains sanitary and storm sewer systems within the city limits. 3.3 Willamette Aquifer The fine-grained soils within approximately 20 feet of the ground surface (Willamette Silts) are not used for water supply directly; however, they may serve as storage and long term recharge for the underlying Willamette Aquifer. 12 Borings completed onsite show the Willamette Silt is between 15 and 20 feet thick. The Willamette Aquifer is predominantly of fanglomerate origin, resulting from deposits of the ancestral Santiam River. The Salem fan is reported to be about 180 feet thick, and is composed of sands, gravels, and cobbles. Ground water flow direction within the aquifer is toward the northwest. 5 Ktec reported that the Willamette Aquifer is confined or semiconfined under the site. 3.4 Water Well Inventory Table 3-1 is largely taken from Ktec, but it is supplemented with additional information and is current to the present time. Note that the table also includes water rights granted within the vicinity of the site and information regarding the down-gradient Oregon School for the Deaf (historical) drinking water supply system. Based on the data presented in the table, no water wells are likely to be impacted by the release at the Withnell property. Known locations are indicated in Figure Woodcock, D.E., 2002 [abstract], Influence of the Willamette Silt on ground-water flow in shallow basin-fill sediments of the Willamette Valley, Oregon: Geologic Society of America, Cordilleran Section, 98 th Annual Meeting. EVREN Northwest, Inc. 11 December 2, 2011

20 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment Table 3-1. Table of Water Wells, Section 14, T. 7 S., R. 3 W. Perforation/Screen Well Number Quarter/ Quarter Section Total Depth (ft.) Area (ft. below ground surface) Aquifer Comments 7170 unknown ft. open hole Basalt Domestic well, drilled in SW of SE unknown unknown unknown Dairy Coop. Assoc. Industrial well, Water Right GR-1856 (non-cancelled), Drilled Located 1,790 feet southwest and cross-gradient from the former Union Station NE of SW Sand and gravel James Garson, Irrigation, Water Right GR-182 (non-cancelled), Drilled Located 1,250 feet northwest of former Union Station SE of NW , , , ft. Basin fill sediments, water level 29 ft. Cascade Meats, Inc., Industrial, Water Right GR-1554 (non-cancelled). Drilled The point of diversion is 1,080 feet north-northeast of former Union Station (cross-gradient) SE of NE Northwest Natural Gas, "Not a Water Well" NW of NE 92 unknown Basin-fill sediments Oregon Nut Growers, Water right GR-4211 (non-cancelled), Industrial and manufacturing, drilled Located 2,180 feet northwest of former Union Station SE of NW 60 unknown Basin-fill sediments Oregon School for the Deaf, Water Right GR-1481 (non-cancelled), institutional domestic and irrigation, drilled The point of diversion is 2,760 feet northwest of the former Union Station (down-gradient). Oregon Drinking Water Program system OR inactive since November 1, No historical detections of petroleum constituents SE of NW 153 unknown Basin-fill sediments Oregon School for the Deaf, Water Right GR-1482 (non-cancelled). Institutional domestic and irrigation, drilled The point of diversion is 2,980 feet northwest of the former Union Station. Oregon Drinking Water Program system OR inactive since November 1, No historical detections of petroleum constituents SW of SW 30 Open below 5 ft. Basin-fill sediments Extraction (gas hydrocarbon) for industry [probable remediation well, no consumption] Basalt G&C Farms, irrigation well SE of SE unknown Basin-fill sediments Willamette Cherry Growers, Manufacturing well, Water Right GR-239 (noncanceled). Drilled before Located 1,400 south and cross-gradient from former Union Station 3.5 Ktec Door to Door Survey Ktec performed a door-to-door survey for wells within a 500 foot radius of the site on April 9, No new wells were identified beyond those indicated on the Table above. However, Ktec reported that the Oregon Cherry Growers indicated they do not currently have a well. The water rights record lists a well for the Oregon Cherry Growers, which was installed before The complete survey is included in the appendix of their 2010 report. EVREN Northwest, Inc. 12 December 2, 2011

21 4.0 HYDROGEOLOGIC CONCEPTUAL MODEL AND LOCALITY OF THE FACILITY The principal release locations for gasoline were in the B3 and B7 vicinity, and the principal release location for diesel and oil appears to have been in the B5 location. Ground water below the site is impacted with gasoline, diesel, and oil constituents. Ground water flows on a general northwesterly course in this vicinity, as indicated by regional hydrogeologic studies e.g., Woodward and others (1998) as well as remediation activities in the northern portion of the Withnell property. Shallow ground water may discharge to Claggett Creek to the northwest (indicated as an intermittent creek on some maps, approximately 2,330 feet from the subject property) or travel over a mile northwest to discharge to the Willamette River. A relatively small amount of discharge from the Willamette Aquifer occurs to irrigation and other wells. However, the beneficial use survey showed that ground water is not used for a drinking water source in the vicinity of the subject property. Since the City of Salem makes its water system available to all residents and businesses, future use of ground water in the vicinity of the subject property is considered unlikely. Recharge is generally from direct precipitation and infiltration where soils are not capped by pavement. Other sources of recharge derive from infiltration at the Willamette Basin margins, irrigation, and from leakage from canals and pipelines. The determination of the LOF considers factors such as: The chemical and physical characteristics of the hazardous substances. The tendency for hazardous substances to migrate through environmental media or to move and accumulate through food webs. Human activities and biological processes that govern the tendency for hazardous substances to move into and through environmental media or to move and accumulate through food webs. The time required for contaminant migration to occur. Site-specific local and regional geology and hydrogeology. Gasoline, diesel, and residual (oil)-related constituents have been shown present in soil and in ground water beneath the subject site. Besides migrating by advection, constituents dissolved in ground water may also: Adsorb onto soil particles. Degrade or chemically react into daughter products. EVREN Northwest, Inc. 13 December 2, 2011

22 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment Volatilize into vadose zone pore space, and then pass into interior or exterior air. Be removed by biologic uptake (since the entire site is paved, and since ground water is generally beyond the rooting zone of most vegetation, the only biologic uptake would probably be by microscopic organisms). Based on the geologic and hydrogeologic setting, known distribution of petroleum impacts, and also on the current and future beneficial uses of ground water, the Ktec Beneficial Use Survey identified a reasonable LOF, defined as the property margins of the Withnell property (Figure 6). EVREN Northwest, Inc. 14 December 2, 2011

23 5.0 RISK ASSESSMENT 5.1 Constituents of Interest Constituents of interest (COIs) are based on hazardous petroleum constituents identified in the RBDM guidance document and listed below: Hazardous petroleum constituents associated with gasoline and diesel releases: Total Petroleum Hydrocarbons (TPH) Gasoline (GRO) Total Petroleum Hydrocarbons (TPH) Diesel (DRO) Total Petroleum Hydrocarbons (TPH) Oil (RRO) Benzene Toluene Ethylbenzene Xylenes 1,2,4-Trimethylbenzene (1,2,4-TMB) 1,3,5-Trimethylbenzene (1,3,5-TMB) 1,2-Dichloroethane (EDC) 1,2-Dibromoethane (EDB) Isopropylbenzene n-propylbenzene Methyl Tert-Butyl Ether (MTBE) Naphthalene Polynuclear Aromatic Hydrocarbons (PAHs) Lead 5.2 Initial Screening of Constituents of Interest An initial screening of COIs is performed by comparing the maximum detected concentration 13 of each COI to the lowest risk-based concentration (RBC) of Appendix A of the RBDM guidance document for all exposure pathways. If the concentration of a detected constituent exceeds the listed screening level, then the constituent is considered a COPC (constituent of potential concern) and is retained for further evaluation. Note that in the screening tables, some analytes were not detected above the analytical method detection limits, but the detection limits for those analytes exceed their lowest RBC (these are indicated by a (Y) in the final columns). ODEQ guidance states a nondetect will be considered acceptable proof that the contaminant is not present, as long as commonly achievable analytical method detection limits are met by ODEQ-approved analytical methods. These analytes will not be identified as COPCs in this risk assessment. 13 This report follows the conservative procedure of using the maximum concentration detected for each constituent of interest (COI) for each media. EVREN Northwest, Inc. 15 December 2, 2011

24 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment Also note that reconnaissance water samples collected during previous site and investigation contained particulates which may have had adsorbed petroleum constituents as well as dissolved constituents. Therefore, reconnaissance water samples have higher reported concentrations than would be indicated by monitoring well data. Reconnaissance water samples are used as a cost-effective and time-effective approximation of ground water impacts Identification of COPCs in Soil Table 1, behind the Table tab of this report, screens the analytical results for residual soil samples in comparison with the screening-level RBC for each COI. The table shows that GRO, ethylbenzene, naphthalene, 1,2,4- and 1,3,5-TMB, and xylenes are the COPCs for subsurface soil at the site. DRO concentrations reported by the laboratory were flagged to indicate that gasoline and oil impacts had biased the reported concentration high, but since DRO does not exceed its screening level RBC, it is not considered a COPC. ODEQ only provides an RBC for RRO as mineral oil; all other oil formulations are regulated on the basis of their hazardous constituents. PAHs were not analyzed and are considered a data gap (see Section 6.0) Identification of COPCs in Ground Water Table 2 shows that GRO, DRO, ethylbenzene, naphthalene, 1,2,4- and 1,3,5-TMB, xylenes, benzo[a]pyene, and benzo[b]fluoranthene are COPCs in ground water. As previously stated, ODEQ only provides an RBC for RRO as mineral oil. All other oil formulations are regulated on the basis of their hazardous constituents, and therefore RRO is not a COPC in ground water. 5.3 Conceptual Site Model The conceptual site model (CSM) of a site identifies complete exposure pathways, where HHRA COPCs in specific media of concern can reach potential receptors. Development of a CSM includes the evaluation of existing and potential reasonable future land use, beneficial water use, and the physical setting of the site, including climate, soil characteristics, and hydrogeology, and general ground water quality. Evaluation of the geology, hydrogeology, and land and water use were detailed in previous sections of this report. Exposure pathways applicable to the site were selected based on current and potential receptors identified both onsite and offsite. Future land-use plans and zoning constraints of the site and surrounding area were reviewed to identify reasonably likely future uses. Wells and water right records on file with the Oregon Water Resources Department and community water system information on file at the OHSDWP were used to evaluate the ground water use in the area. Fate and transport of site-related chemicals also were considered in the evaluation of potential exposure pathways Media of Concern Residual impacts exist in subsurface soil and ground water at the site. EVREN Northwest, Inc. 16 December 2, 2011

25 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment Land Use and Ground Water Use Identification of Potential Receptors The following was taken into account to establish current and reasonably likely future land use within the LOF: Current land use Zoning, comprehensive plan or other land use designations Land use regulations from any governmental body having jurisdiction Concerns of the owner, the neighboring owners and the community Other relevant factors The site is currently zoned Industrial Commercial (IC) and is located in the Pine Street IC Mixed-Use Area of the Portland/Fairgrounds Road Overlay Zone (Section 3.1). Occupational workers are likely to be present on the property in the future. There is no current residential use in the LOF, and future residential use in the LOF is unlikely as the site is bounded by a railroad easement and is located in a predominantly commercial area around the intersection of Portland Road NE and Silverton Road and the State Fairgrounds. However to be conservative, this risk assessment will include residential receptors. It is conceivable that the site will be redeveloped in the future and construction workers and excavation workers will be present on the site Pathways of Concern An exposure pathway is the course a constituent takes from a source to an exposed population. Exposure pathways include four elements: (1) The source of contamination. (2) The means by which a constituent will be released, retained, or travel in a given medium (e.g., air or ground water). (3) A point of potential contact with a receptor. (4) The means by which contact will occur (e.g., inhalation, ingestion). If any of these elements is missing, the pathway is considered incomplete. Table 5-1 presents the results of exposure pathway screening using the reasoning presented in ODEQ s RBDM guidance document. Occupational workers and construction workers should not come into dermal contact with impacted subsurface soils. However, volatiles in impacted soil may enter interior and exterior airspace and be inhaled by occupational and construction workers. Excavation workers may come into dermal contact with impacted soils, and additionally may incidentally inhale and ingest impacted soils. EVREN Northwest, Inc. 17 December 2, 2011

26 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment Water is available to the site from the municipal water system (e.g., the now vacated DMV building). There are no water wells on the subject property. However, impacted ground water may allow dissolved volatile constituents to volatilize into interior and exterior air space, where they may be inhaled by occupational workers and excavation workers. The exposure pathways are summarized in Table 5-1 and illustrated in Figure 7. Table 5-1. Exposure Pathway Applicability Medium Receptors Exposure Pathway Retained? Dermal absorption No. Impacts are too deep to be directly contacted by occupational workers. Volatilization to outdoor air YES. Vadose zone soils are impacted with volatile COPCs. Occupational YES. Vadose zone soils are Workers, Future impacted with volatile COPCs, Volatilization to indoor air and may be present within 10 Residents feet of a future commercial Soil building. No. Municipal water is provided Leaching to ground water to the subject property, and drilling of a water well in the future is unlikely. No. Impacts are too deep to be Construction Worker Dermal contact directly contacted by construction Ground- Water Excavation Worker Occupational Workers, Future Residents Excavation Worker Dermal contact-incidental ingestion and inhalation Dermal absorption Volatilization to outdoor air Volatilization to indoor air Ingestion Dermal contact-incidental ingestion and inhalation workers. YES. Impacted soils may be directly contacted by an excavation worker. No. Ground water is too deep to be contacted by an occupational worker. YES. Ground water impacts include volatile compounds. YES. Ground water impacts of volatile compounds may be located within 10 feet of a future commercial building. No. Municipal water is provided to the subject property, and drilling of a water well in the future is unlikely. YES. Ground water is encountered between 18 and 20 feet onsite, but is under confined or semi-confined head. To be conservative, this risk assessment will consider this pathway. 5.4 Identification of Constituents of Concern The following tables compare COPCs with the RBCs for the applicable complete pathways and receptors of potential concern to identify constituents of concern (COCs). EVREN Northwest, Inc. 18 December 2, 2011

27 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment Subsurface Soils Table 3 shows that ethylbenzene, naphthalene, 1,2,4- and 1,3,5-TMB, and GRO exceed the RBCs for complete pathways for residential receptors, principally for intrusion into interior air. Additionally, naphthalene exceeds its RBC for volatilization to outside air for residential receptors. However, as previously discussed, future residential use is unlikely at this property. No COPCs present an unacceptable health risk to potential occupational workers or excavation workers Ground Water Table 4 shows that the COPCs do not present an unacceptable risk to any potential future receptors by the complete pathways. 5.5 Evaluation of Risk To The Environment No sensitive environmental features or receptors were identified in the LOF. EVREN Northwest, Inc. 19 December 2, 2011

28 6.0 DATA GAP ANALYSIS 6.1 Soils The current site data provides an adequate characterization of GRO impacts at the site. GRO impacts have been delineated to the south, east, and north, and it is believed that the soil removal performed by GeoEngineers under the sidewalk at the location included all impacted soils at that location (per their Scope of Work and as described in their letter report 7 ), although vertical delineation sampling at that location and westward delineation under Portland Avenue NE have not been performed. Additionally, adjacent sampling to the south at GeoEngineers and sampling locations and to the north at the location of (all three are nondetect samples for all ranges of TPH) suggest that any westward lobe of the soil plume from the sidewalk alignment would be very limited in extent. The B5 location appears to be the principal location where RRO and DRO were released (other than the two GeoEngineers detections). The DRO and RRO impacts at Boring B5 total 4,240 mg/kg. However, the diesel impacts were flagged by the laboratory to indicate that the diesel result was biased high because of the impacts in the adjacent gasoline (weathered gasoline) and residual (oil) ranges. Additionally, there were no RRO or DRO data to the north, northeast, or east of the B5 location. The absence of delineation data in these directions is considered a data gap. Furthermore, there is no PAH data for DRO/RRO detections, which is considered a data gap when considering dermal contact, inhalation and ingestion pathways. 6.2 Reconnaissance Ground Water GRO impacts to ground water are greatest at the B3 and B7 boring locations, in accord with the findings for soil impacts. GRO was below the analytical method detection limits at B4, B5, and B6. Therefore, the northward extent of ground water impacts is delineated. Since ground water has been documented as flowing to the northwest in this vicinity, the B6 data in part delineates the northwestward extent. However, since GRO impacts to ground water were detected at up to 4,050 mg/kg at the B7 location, there is some uncertainty regarding the northwestward extent of the ground-water plume from that location, and is considered a data gap. DRO and RRO impacts to ground water also are highest at the B3 location, and attenuate in a similar pattern to GRO. Therefore, diesel and oil impacts are not fully delineated toward the northwest (down-gradient). Lead was not analyzed in reconnaissance ground water samples. However, since lead was not indicated to be enriched in any of the soil samples, it is unlikely lead is a constituent of concern in reconnaissance ground water. However, since any future residential land use to the northwest (across Portland Road NE) is at a relatively large distance, and since the municipal water supply will probably be used EVREN Northwest, Inc. 20 December 2, 2011

29 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment for any residential development in that area, and RRO was eliminated as a COPC, this ground water data gap may not be significant. Ktec concluded from their beneficial use survey that there are no beneficial uses of ground water within one-quarter mile of the subject property. 6.3 Discussion The data gaps were identified concerning DRO and RRO delineation in soils and the lack of any PAH data for the soil impacts in the vicinity of the Boring B5. As shown in the risk assessment, DRO, RRO, and PAHs are unlikely to present an unacceptable health risk at the subject property because of the depths of soil impacts and their limited volatility. Any risk to excavation workers can be addressed in a Contaminated Media Management Plan. If a title restriction were to be implemented prohibiting future residential use, future use of the ground water resource, and adherence to a Contaminated Media Management Plan, there would be no unacceptable risk to current or future human receptors. The deed restriction would have to remain in effect until future remediation or additional investigation shows that risks have been reduced to acceptable levels. EVREN Northwest, Inc. 21 December 2, 2011

30 7.0 CONCLUSIONS AND RECOMMENDATIONS Residual impacts from petroleum hydrocarbons and associated constituents are present in subsurface soil and ground water, as documented by Ktec. Therefore, a risk assessment was performed to evaluate potential health risks to current and future human receptors. Analytical data for soil and ground water were initially screened against the most conservative RBC of all exposure pathways for each analyzed COI. This initial screening identified GRO, ethylbenzene, naphthalene, 1,2,4- and 1,3,5-TMB, and xylenes as COPCs for subsurface soil at the site. GRO, DRO, ethylbenzene, naphthalene, 1,2,4- and 1,3,5- TMB, xylenes, benzo[a]pyene, and benzo[b]fluoranthene are COPCs in ground water. A conceptual site model was then developed to identify complete pathways by which human receptors could be exposed to hazardous petroleum constituents. Occupational workers and excavation workers were identified as the primary human receptors, but this risk assessment also included residential receptors to be conservative. Yet, since this site is located in a commercial area adjacent to a railroad track, although future residential use is allowed under the current zoning designation it is considered unlikely. Further risk evaluation determined that impacted soil and ground water do not present an unacceptable health risk to occupational or excavation workers. However, volatile constituents in residual soils may present an unacceptable health risk to residential receptors by intrusion into interior air. Additionally, naphthalene may present an unacceptable health risk by volatilization to exterior air, followed by inhalation of a resident. The data gaps concerning diesel and oil delineation in soils and the lack of any PAH data for the soil impacts in the vicinity of the Boring B5 can be addressed in a Contaminated Media Management Plan, since DRO, RRO, and PAHs are unlikely to present an unacceptable health risk at the subject property because of their depth and limited volatility. ENW recommends that the property should receive regulatory closure with deed restrictions (equitable easement and servitude) stipulating: 1) Prohibition of future residential use of the property. However, residential use could be granted in the future if engineering controls were utilized during construction, or remediation were conducted followed by additional investigation and assessment of risk, or a soil vapor assessment could be conducted to further evaluation the vapor intrusion pathway; 2) Prohibition of installation of any water wells for drinking water or other use, and; 3) Adherence to a Contaminated Media Management Plan to be developed for the property. The Contaminated Media Management Plan should stipulate hazardous materials management and disposal procedures, as well as ensure safe working conditions for future site workers. EVREN Northwest, Inc. 22 December 2, 2011

31 Former Union Oil Service Station, Salem, OR (Withnell Property) Risk Assessment The deed restrictions should remain in effect until future investigation or future remedial actions demonstrate that the above stipulations are no longer required to protect future human receptors at the site. EVREN Northwest, Inc. 23 December 2, 2011

32 8.0 LIMITATIONS The scope of this report is limited to observations made during on-site work; interviews with knowledgeable sources; and review of readily available published and unpublished reports and literature. As a result, these conclusions are based on information supplied by others as well as interpretations by qualified parties. The focus of the site closure does not extend to the presence of the following conditions unless they were the express concerns of contacted personnel, report and literature authors or the work scope. Naturally occurring toxic or hazardous substances in the subsurface soils, geology and water. Toxicity of substances common in current habitable environments, such as stored chemicals, products, building materials and consumables, Contaminants or contaminant concentrations that are not a concern now but may be under future regulatory standards. Unpredictable events that may occur after ENW s site visit, such as illegal dumping or accidental spillage. There is no practice that is thorough enough to absolutely identify the presence of all hazardous substances that may be present at a given site. The cleanup investigation has been focused only on the potential for contamination that was specifically identified in the SOW. Therefore, if contamination other than that specifically mentioned is present and not identified as part of a limited SOW, the environmental investigation shall not be construed as a guaranteed absence of such materials. ENW has endeavored to collect representative analytical samples for the locations and depths indicated in this report. However, no sampling program can thoroughly identify all variations in contaminant distribution. ENW has performed services for this project in accordance with the agreement and understanding with the Client. This document and the information contained herein have been prepared solely for the use of the Client. The remediation team performed this study under a limited scope of services per the agreement. It is possible, despite the use of reasonable care and interpretation, that ENW may have failed to identify regulation violations related to the presence of hazardous substances other than those specifically mentioned at the closure site. ENW assumes no responsibility for conditions that were not specifically evaluated or conditions that were not generally recognized as environmentally unacceptable at the time this report was prepared. EVREN Northwest, Inc. 24 December 2, 2011

33 FIGURES

34 Source: USGS Salem West Quadrangle, Oregon, 1969, Photorevised Date Drawn: 10/31/2011 CAD File Name: svmap Drawn By: LDG Approved By: NMW Former Union Oil Facility 2540 Portland Road NE Salem, Oregon Site Vicinity Map Project No Figure No. 1

35 PINE ST NE PARKING PORTLAND RD NE PARKING DMV SILVERTON RD NE FIGURE 2 SITE PLAN

36 GAS STATION MA WALL? WAREHOUSE DRYWELL FILLING SHED NATURAL GAS RESIDENCE MA MA OFFICE RESIDENCE MA MA PARKING PARKING FIGURE 3 SITE PLAN WITH HISTORICAL FEATURES FORMER UNION OIL FACILITY 2540 PORTLAND ROAD NE SALEM, OREGON RESTAURANT MA MA GAS STATION

37 6 VP-1 0 VP VP-2 ~10 B-1 VP-3 ~ FIGURE 4 PREVIOUS SAMPLE LOCATION DIAGRAM FORMER UNION OIL FACILITY 2540 PORTLAND ROAD NE SALEM, OREGON

38 FIGURE 5 ZONING MAP FORMER UNION OIL FACILITY 2540 PORTLAND ROAD NE SALEM, OREGON

39 Source of Base Map: Oregon Water Resources Department. Locality of Facility 8152 Well Identification Water Right Place of Use Place of Diversion Date Drawn: 10/31/2011 CAD File Name: (LOF)Figure-6 Drawn By: LDG Approved By: NMW Former Union Oil Facility 2540 Portland Road NE Salem, Oregon Locality of Facility Project No Figure No. 6