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Former Brien Ford Property <br /> Everett, Washington Phase I1 Supplemental Site Investigation <br /> • Gasoline-range petroleum hydrocarbons (GRPH) by Northwest Total Petroleum <br /> Hydrocarbon (NWTPH) Method NWTPH-Gx; <br /> • Diesel-range and oil-range petroleum hydrocarbons (DRPH and ORPH) by NWTPH <br /> Method NWTPH-Dx; and <br /> • VOCs by EPA Method 8260C (at locations GP-18 and GP-21). <br /> Complete analytical laboratory reports and sample chain-of-custody forms are attached. <br /> SUBSURFACE INVESTIGATION RESULTS <br /> Subsurface conditions at the project site were based upon conditions observed in the field <br /> explorations completed for this study. Because of the nature and limitations of subsurface <br /> exploratory work, extrapolation of subsurface conditions between field explorations is <br /> necessary. Differing subsurface conditions may be present between exploration locations due <br /> to the random nature of deposition and the alteration of topography by past grading and/or <br /> filling. The nature and extent of any variations between the field explorations may not become <br /> fully evident until future remediation, construction, or redevelopment occurs. <br /> Subsurface Soil and Ground Water Conditions <br /> Concrete was encountered in borings GP-13, GP-14, GP-18, GP-21, GP-28, and GP-29 between <br /> the surface and 4 inches bgs with the exception of GP-28 which encountered 8 inches of <br /> concrete and GP-29 which encountered 6 inches of concrete. Asphalt was encountered in all <br /> other borings between the surface and 3 inches bgs, with the exception of GP-22 which <br /> encountered 4 inches of asphalt. All borings encountered fill soils below the asphalt. <br /> All of the exploration borings encountered sediments interpreted to be Vashon ice-contact <br /> deposits below the fill and asphalt/concrete, except GP-18. Boring GP-18, bored to a total <br /> depth of 5 feet due to refusal, did not extend into the Vashon ice-contact deposits underlying <br /> the fill soils. The sediments comprising the ice-contact deposits had highly variable densities <br /> and composition. <br /> Vashon advance outwash deposits were encountered beneath the ice-contact deposits at <br /> depths ranging from 7 to 12 feet bgs in eleven of the borings. The advance outwash deposits <br /> extend down to the maximum depth explored. <br /> Several discontinuous water-bearing zones were encountered at depths ranging from about <br /> 6 to 16 feet bgs in borings GP-15, GP-16, GP-19, and GP-24. The localized saturated intervals <br /> were encountered within relatively thin layers/lenses of permeable sediments within the <br /> ice-contact deposits and the upper few feet of the underlying advance outwash deposits. <br /> Water-bearing zones were not encountered in the other borings completed and sampled during <br /> this Phase II SSI. <br /> March 31,2017 ASSOCIATED EARTH SCIENCES,INC. <br /> TWL/Id-20160594V002-2-Projects\20160594\KV\WP Page 4 <br />