February 8, Mr. Jeff Vanderdasson, P.E. PACLAND 6400 SE Lake Road, Suite 300 Portland, Oregon 97222

Transcription

1 Mr. Jeff Vanderdasson, P.E. PACLAND 6400 SE Lake Road, Suite 300 Portland, Oregon Re: Phase I Environmental Site Assessment Recommendations Letter NW 9th Street and NW Spruce Avenue Corvallis, Benton County, Oregon Dear Mr. Vanderdasson: Terracon Consultants, Inc. (Terracon) is pleased to submit this Phase I Environmental Site Assessment (ESA) Recommendations Letter for the above referenced site. As stated in the Retailer s Environmental Due Diligence Policy, Standards and Protocols and Guidance, recommendations for further environmental assessment or other action shall not be made a part of a Phase I ESA report, as such are included herein. The recommendations letter is intended to be used in conjunction with, and under the same standard of care, conditions and limitations as described in our Updated Limited Site Investigation (Project No A dated February 2, 2102) and Phase I ESA for the site (, report dated February 8, 2012) and provided under separate covers. Findings and Conclusions Based on the scope of services and limitations of the Updated Limited Site Investigation (LSI Report dated February 2, 2012) and Phase I ESA (report dated ), Terracon identified the following Recognized Environmental Conditions (RECs): Utility pole treatment and transformer maintenance operations at the former CPI facility that included the subject site resulted in soil and/or groundwater contamination with PCP, dioxins/furans, PCE (groundwater), and minor amounts of PCBs, Halogenated VOCs (PCE and TCE), VAH (volatile aromatic hydrocarbons), TPH, chlorinated phenolics, and PAHs. The CPI-related soil and groundwater contamination represents a REC in connection with the site. Circle 9 Dry Cleaners operated at 960 NW Circle Avenue from 1960 through This facility was located approximately 250 feet northwest and up-gradient from the site. PCE releases to soil and groundwater have been documented at this nearby facility. PCE-contaminated groundwater has been documented on the northern portion of the Terracon Consultants, Inc SE International Way, Suite 300 Portland, OR P [503] F [503] terracon.com

2 CPI facility in the vicinity of the site that appears to have originated from the former Circle 9 Dry Cleaners. The Circle 9 Dry Cleaners represents a REC in connection with the site. Therefore, risks associated with the former CPI facilities and the off-site former Circle 9 Dry Cleaners were assessed via a limited subsurface investigation in the vicinity of the proposed Walmart tenant space. A Limited Site Investigation (or LSI, Terracon Project No A, LSI Report dated February 2, 2012) was conducted by Terracon. The full LSI report should be reviewed for a complete discussion of findings and recommendations. Fifteen subsurface explorations, with ten associated temporary groundwater monitoring wells, were advanced in August of 2011 to maximum depths of 35 feet bgs. A total of 25 soil samples were collected. These consisted of ten soil samples in areas potentially to be disturbed during development of exterior improvements (3-6 feet bgs); ten soil samples near the clayey silt/sandy gravel interface (30-35 feet bgs), which previous reports indicated is the zone most likely to be impacted; and five soil samples from the uppermost native soil within the proposed building footprint to evaluate soils that may be disturbed during construction of the building. A total of 25 soil samples and 12 groundwater samples were collected. Soil samples and groundwater samples were analyzed for gasoline, diesel, and oil range total petroleum hydrocarbons (TPH); Volatile Organic Compounds (VOCs); Polycyclic Aromatic Hydrocarbons (PAHs); RCRA 8 Metals; Pentachlorophenol (PCP); and Polychlorinated Biphenyls (PCBs). Additionally, all soil samples and seven groundwater samples collected from select borings were analyzed for dioxins and furans. Laboratory analytical results were compared to Oregon DEQ RBCs applicable to occupational, construction workers, and excavation worker receptors for potentially complete exposure pathways. The results are summarized below: TPH, VOCs, PAHs, PCBs, and PCP were not detected in soil in concentrations above the laboratory Reporting Detection Limits (RDLs) with the exception of bromomethane. The concentration of bromomethane did not exceed RBCs established for occupational, construction, and excavation workers. RCRA 8 Metals were detected in soil at concentrations above the laboratory RDLs; however only arsenic was detected at concentrations above RBCs established for occupational, construction, and excavation workers. Several dioxins and furans were detected in soil at concentrations above the laboratory Method Detection Limits (MDLs) but below the RDLs, indicating these compounds were present in the sample but at an estimated concentration below the lowest equipment calibration point. Only 1,2,3,4,6,7,8-Hepta Chloro Dibenzo-p-Dioxin (CDD) and 1,2,3,4,6,7,8-Hepta Chloro Dibenzo-p-Furan (CDF) were detected at concentrations Responsive Resourceful Reliable 2

3 exceeding the laboratory RDLs. Currently DEQ does not have established RBCs for 1,2,3,4,6,7,8-Hepta CDD or 1,2,3,4,6,7,8-Hepta CDF. However, the concentrations detected did not exceed the most stringent DEQ RBC (Leaching to Groundwater) for 2,3,7,8-Tetra CDD or the EPA RSLs after applying the Toxicity Equivalency Factors (TEFs) to these compounds. Petroleum hydrocarbons, PAHs, PCBs, and PCP were not detected above the laboratory RDLs in groundwater. Cis-1,2-dichloroethene; trans-1,2-dichloroethene; tetrachloroethene (PCE); and trichloroethene (TCE) were detected at concentrations above the laboratory RDLs; however the detected concentrations did not exceed the DEQ RBCs established for occupational and construction worker receptors. The remaining VOC constituents analyzed were not detected above the laboratory RDLs. Several RCRA 8 Metals were detected above the laboratory RDLs; however the detected concentrations did not exceed the DEQ RBCs established for occupational, construction, and excavation workers. 1,2,3,4,6,7,8-Hepta CDD; 2,3,4,7,8-Penta CDF; Octa CDD; Octa CDF; and 2,3,7,8-Tetra CDF were detected above the laboratory MDLs but below the RDLs. These results indicate that the compounds are present, but in very low, estimated concentrations. The reported concentrations did not exceed the most stringent DEQ RBC established for a completed pathway at the site (groundwater in excavation) for TCDD, which is the index chemical for TEF comparison. Recommendations Based on the findings of the LSI and Phase I ESA, Terracon makes the following recommendations: The release of chlorinated solvents from the Circle 9 Dry Cleaners currently has an open DEQ file and this site does not appear to have been remediated at this time. In addition, based on the results of our LSI which detected PCE and TCE in groundwater, the release has migrated onto the northern portion of the subject site. As a result, the Circle 9 Dry Cleaners is still considered to be a REC to the site. However, because the concentrations of chlorinated solvents detected during the LSI do not appear to exceed vapor intrusion, occupational, excavation/construction worker RBCs, no further investigation is recommended at this time. Groundwater is not used for drinking water at the site. In addition, although a DEQ Record of Decision is in place for the CPI site, because of known impacts to the site from the former CPI operations, and ongoing restrictions regarding soil and groundwater management as outlined in the Amended SMP, the CPI Responsive Resourceful Reliable 3

4 site is also still considered a REC to the site. However, based on the information collected during the LSI and previous investigations by others (which indicate that contaminants on the subject site are below applicable RBCs), and the existence of a DEQ approved Amended SMP for the CPI site, no further investigation is recommended at this time. Arsenic was detected at concentrations below excavation worker RBCs, but above occupational and construction worker direct contact RBCs. Potential direct contact between occupational workers and onsite soils should be minimized by maintenance of the asphalt cap (parking area) at the site. Construction workers should be notified that arsenic in soil exceeds the direct contact RBC, and that appropriate health and safety procedures should be implemented to limit exposure. An Amended SMP, dated December 14, 2011, has been prepared by GeoDesign and has been submitted to and approved by DEQ. The Amended SMP addresses the handling of soils during construction. Terracon recommends that all construction and related earthwork activities be performed to comply with the conditions and requirements of the Amended SMP dated December 14, In addition, we recommend Terracon be authorized to observe Walmart s earthwork activities and document the location and depth of soils disturbed during construction, and document the final disposition of the disturbed soils. Business Environmental Risk Recommendations Terracon recommends the following with regard to potential business environmental risks impacting future development of the Corvallis, Oregon site: A professional archeologist should be consulted in the event that suspect cultural resources are revealed during site development activities. Responsive Resourceful Reliable 4

5 Closure Terracon appreciates the opportunity to perform these services for PACLAND. Please contact us if you have questions regarding this information or if we can provide additional services. Sincerely, Terracon Consultants, Inc. Gary R. Henningsen, P.G. Senior Project Geologist Lon R. Yandell, R.G. Environmental Departmental Manager cc: Scott Franklin, P.E. - PACLAND Responsive Resourceful Reliable 5