HomeMy WebLinkAbout21-100244-SU-TSP Geotechnical Report-01-25-2021-V19Cons{ - TERRA ASSOCIATES, Inc. . •, + • ultants in Geotechnical Engineering, Geology and Environmental Earth Sciences May 5, 2020 Project No. T-8347-1 Mr. Geoffrey P. Sherwin Director of Acquisitions and Entitlement JKM Holdings, LLC P.O. Box 188 Puyallup, Washington 98371 Subject: Tacoma Smelter Plume (TSP) Impact Overview South Campus Estates Southeast of intersection of SW 366th Street and 6th Avenue SW Federal Way, Washington Pierce County Tax Parcel 3021049041 Dear Mr. Sherwin: This memo presents the findings of our overview of possible impacts to the site regarding the Tacoma Smelter Plume (TSP) Site. Below is a summary of our findings based on site reconnaissance, review of Ecology's available on-line interactive TSP Map, and email correspondence with an Ecology representative. We visited the site on May 1, 2020 to observe current site conditions. The site consists of one 4.73-acre parcel and is currently undeveloped forested land with a thick understory. We did not observe any trails or roads providing access to the site interior. Trees comprising the forest appeared to be at least 30 to 40 years old. We did not observe any stockpiled soils or signs of recent grading activity. We reviewed the current Interactive TSP Map on-line at https:Hgpps.ecology.wa.gov/dirtalert/. The map depicts concentrations of known impacts from the TSP in the Puget Sound region. The site is beyond the distal margins of plume impacts. The subject site and vicinity are shown in an area with predicted arsenic concentrations less than 20 part per million (ppm). The nearest areas shown with predicted arsenic concentrations above 20 ppm is approximately 2 miles west of the subject site. 20 ppm is the current MTCA Method A cleanup level for soil for unrestricted land use. 12220 113th Avenue NE, Ste. 130, Kirkland, Washington 98034 Phone (425) 821-7777 • Fax (425) 821-4334 Mr. Geoffrey P. Sherwin May 5, 2020 We contacted Ms. Eva Barber, Technical Assistance Coordinator of the Toxics Cleanup Program at Ecology's Southwest Regional Office for the TSP program, via email. Ms. Barber indicated that we can rely on the on-line Interactive TSP Map in determining whether sampling site soils for TSP impacts is warranted. Based on our site observations, review of the on-line Interactive TSP Map, and our correspondence with Ecology, it is our opinion that testing site soils for TSP impacts is not needed. The site is mapped in an area with no impacts above current applicable cleanup standards. We trust the information presented is sufficient for your current needs. If you have any questions or require additional information, please call. Sincerely yours, TERRA ASSOCIATES, INC. Nicolas R. Hoffinan, L.G. Senior Project Geologist Charles R. Lie, L.H.G. Project Manager CHARLES R. uE Project No. T-8347-1 Page No. 2