721 E MARINE VIEW DR 2016-01-01 MF Import

Till material deposited during tha Vashon glaciation covers the surface of coastal pleteau blocks to an average dept6 of about SO feet and is as much as 150 t6ick in places. Everett lies ou the coastal plateau block __ known as the "Intercity Pleteau" occucriog betweeo Puget Sound and the Sno6omish River. The till remains on many of the msrginal slopes of the plateau blocks. Bene�th the till on the Intercity Plateau, lias a thick zane of sand and gravel, t6e Fsperence Sand member. In some places, the entiro deposit is saturated wit6 water and is considered t6e most impoRant ground-water body that occurs beneaW the Intercity Plateau. The — Vashon till wvering the Everett enea is largely impermeable and, theroforo, a poor aquifcr, although gravel streaks within t6e till could concentrate shellow ground-water end create small "penched" aquifers. 'Ibe elevation at the Site is epproximately between ]00 and I15 feU aUove mean sea level with the natural terrain sloping genUy east towud the Snahomish River. No evidence of spriags or other groundwater rnnoff wero observed along the 6illside on eastern poRion of the Siu. This would indicate that "pec�chad" groundwater is probably not present at t6e Site. Ground-water would most likely occur betwxn 50 and 100 fcet below the natueal ground surfecx of the Site and would migcate in a easterly direction, towarct the Soohomish River. 4.0 SCOPE OF WORK 7Le rationele for t6e scope of wodc was to collect surface and subsurFace soils for chemical analysis to eveluate if a potential environmental risk exists at the site associated with coastruction debris and the "sand cap" on the nonh parcel, and potentiel off-site sounces for both the noRh and sout6 parcels. 'Ihe iniNal scope of work included: • excava8on of four test pits to 10 feet bgs on the noAh pamel for the collxtion of eight subsurface soil samples for chemical amlysis of total pe.roleum hydmcarbons (TPI� and heavy metals (atsenic, bsrium, cadmium, chromium, lead, mercury, selenium, silver, and zine), • collection of subsurface soil semples from t6roe hanQ-auger borings located at the toe of the fill slope on the noRh pancel for chemical aoalysis of TPH and heavy metals and three hand-auger borings aceally distributed ova the south percel for the chemical analysis of heavy metals (samples collected from hand-auger borings were wmposited fi+om three discrete samples collected at one,two and three feet 68s), , • collection of one surface soil sample from the "sand cap" material for c6emical analysis of 6eavy metals, and • preperstion of a report summarizing the results of the field progrem aad analytical results. Based on the analytical results of soil samples wllected during the initiel scope of work, the following additionel work was performed: • excavation of five test piu to 10 feu bgs on the north parcel for the collection of ten subsurface soil samples for chemical analysis of TPH and volatile organic compounds �Sve samples), and • collection of hvo surface soil samples from sediment � �Iged from the Snohomish River and stockpilad at Lengus Pazk for chemical analysis of TPH an.. 5eavy metals. 4