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June 29, 2017 | Page 1 File No. 0504-119-00 <br />1.0 INTRODUCTION <br />This report describes second quarter 2017 groundwater monitoring activities conducted at the Kittitas <br />County Lower Shop site located at 505 West 14th Avenue in Ellensburg, Washington (herein referred to as <br />“site”). The approximate site location is shown in the attached Vicinity Map, Figure 1. <br />Site environmental activities are managed by the Washington State Department of Ecology (Ecology). This <br />report describes field activities, observations and chemical analytical results associated with groundwater <br />samples collected at the site. The purpose of the overall assessment activities associated with this project <br />was to further define the extent of soil and groundwater contamination beneath the site associated with <br />former underground storage tank (UST) operation. <br />2.0 PREVIOUS ASSESSMENT <br />GeoEngineers conducted a soil and groundwater assessment on December 1, 2016 (GeoEngineers 2016). <br />Benzene and gasoline-range petroleum hydrocarbons (GRPH) were detected in soil samples collected from <br />borings B-1 and B-2 at concentrations greater than the Washington State Model Toxics Control Act (MTCA) <br />Method A unrestricted land use cleanup levels. <br />GRPH, diesel- and oil-range petroleum hydrocarbons (DRPH and ORPH, respectively) also exceeded MTCA <br />Method A cleanup levels from a grab groundwater sample collected from soil boring B-1. Boring locations <br />are shown in the attached Site Plan and May 2017 Groundwater Elevations, Figure 2. <br />A prior environmental report (Terragraphics 2014) for the site identified one existing groundwater <br />monitoring well on the property. This well was located during the December 2016 site assessment, and <br />three additional wells were located. The four existing well locations (MW-1, MW-4 through MW-6) were <br />re-labeled in the field as shown on Figure 2. Two additional wells (MW-2 and MW-3) were installed during <br />our recent assessment activities for a total of six groundwater monitoring wells on site. <br />The first quarter 2017 groundwater monitoring event (GeoEngineers 2017) was conducted in March 2017. <br />GRPH, benzene and total xylenes were detected in the monitoring well MW-2 sample; however, the reported <br />concentrations did not exceed MTCA Method A cleanup levels. <br />3.0 SCOPE OF SERVICES <br />The scope of services included the following: <br />1. Coordinate subcontractors (TestAmerica Laboratories, Inc. [TestAmerica]) and provide project <br />management services. <br />2. Performing the second quarterly groundwater monitoring event. Water quality parameters (pH, <br />temperature, oxidation-reduction potential [ORP], turbidity, dissolved oxygen [DO] and conductivity) <br />were measured and documented while purging each well. Six groundwater samples were collected <br />from the four existing wells (MW-1 and MW-4 through MW-6) and the two recently installed monitoring <br />wells (MW-2 and MW-3); one duplicate groundwater sample was collected from well MW-3. <br />Groundwater samples were submitted to TestAmerica for the following laboratory analyses: