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HomeMy WebLinkAboutRS_Environmental Site Asssesment_20180803STEMENENVIRONMENTAL, INC. P.O. BOX 3644 LACEY, WASHINGTON 98501-8212 CONTR. LIC. #STEMEEI081J9 Telephone 360-438-9521 Fax 360-412-1225 April 23, 2018 Mr. Dale Walker D & C Investments, LLC 555 SW Grady Way Renton, Washington 98057 Dear Mr. Walker: RE: LIMITED PHASE II ENVIRONMENTAL SITE ASSESSMENT, GROUNDWATER MONITORING WELL INSTALLATION, AND GROUNDWATER MONITORING INFORMATIONAL LETTER FOR THE COMMERCIAL PROPERTY LOCATED AT 3400 EAST VALLEY ROAD, RENTON, WASHINGTON. TAX PARCEL #302305-906 1.0 Site Characteristics The assessed property, herein described as the subject property, is composed of 5.65 acres (246,114 square feet) of commercially developed property located at 3400 East Valley Road, Renton, Washington. The King County Assessor’s Office lists the subject property as Tax Parcel #302305-9067. Based on the review of aerial photos, Polk Street Directories, knowledgeable individuals, and information obtained from the King County County Assessor's Office, it appears that for approximately 64 years the subject property has been primarily occupied by an automotive wrecking yard and/or radiator shop. Available information indicates that in earlier years, the property was vacant undeveloped farm/agricultural land. The subject property is located in an area primarily occupied by commercial/industrial properties and a State Highway. A Wetland is located along the eastern boundary of the subject property. Current development of the subject property consists of a single story, 4,000 square foot Pre-Fabricated steel ware house building and an approximately 1,100 square foot radiator shop. The radiator shop structure is a three sided, covered building built on a concrete slab. The subject property is serviced by public utilities. 2 A large portion of the gravel/dirt surface property is used for the storage of disabled/junk cars, associated car parts, and petroleum products liquid storage containers. The perimeter of the property is secured by a chain link security fence. 2.0 Investigative Soil and Groundwater Sampling Projects On March 29 and March 30, a total of twenty-nine (29) borings were advanced at selected locations on the subject property. On February 15, 2018, twenty (20) additional soil borings were at selected locations on the subject property The borings were advanced to approximate depths of 10 feet b.g.s. or less at selected accessible locations throughout the subject property. Soil samples were obtained from various depths at each sampling location. Groundwater samples were obtained from eight (8) of the borehole sampling locations. Additionally, one (1) groundwater sample was obtained from an "out of service" water well located along the southern portion of the western perimeter of the subject property. The well was discovered during on-site investigations in the immediately surrounding areas. After the water in the well was sampled and the receipt of laboratory analyses results, the well was property closed/abandoned by Licensed Well Drillers from Holt Services Inc. Soil samples were field screened using a water sheen test and a Photo-ionization Detector (PID). A total of forty-five (45) soil samples and nine (9) water samples were submitted for extended laboratory analyses based on on-site observations and field screening results. 3.0 Preliminary Investigations Findings The surface soils and very shallow subsurface soils present on large sampled portions of the subject property are oil stained and require removal and proper off-site disposal. The soils present at depths of 4 ft. b.g.s. (below ground surface) or greater in many of these areas do not contain petroleum range contaminates and/or VOCs at levels that exceed MTCA Method A Clean Up Levels and would not require removal. The results of these environmental investigations report no presence of Hexavalent Chromium (Chrome VI) in the shallow subsurface soils on the subject property. Area #1 - North Central Portion of Site The subsurface soils present at depths up to at least 10 ft. b.g.s., in an area occupied by liquid storage drums on the central northern portion of the subject property (Sampling Location 3 S-8), contain gasoline range petroleum contaminates at levels that exceed MTCA Method A Clean Up Levels. The groundwater sampled at sampling location S-8 contained gasoline range TPH (total petroleum hydrocarbons), Benzene, and MTCA 5 Metals at levels that exceed MTCA Method A Clean Up Levels. Area #2 - Radiator Shop Area The shallow subsurface soils located in areas directly surrounding the on-site radiator shop building and the adjacent liquid storage drum area contain VOCs (volatile organic compounds), gasoline range TPH, diesel fuel range TPH, and lube oil range TPH and Lead that exceed MTCA Method A Clean Up Levels. The groundwater in areas directly surrounding the on-site radiator shop building contain MTCA 5 Metals at levels that exceed MTCA Method A Clean Up Levels. Area #3 - Southern Portion of Western Perimeter of Site A liquid drum storage area and a few small automobile work area compounds are located on this portion of the site. Aerial photos depict that portions of this area periodically serve as a storm water collection area for oily storm waters. An "out of service" 8 inch diameter steel well casing was found along the western perimeter of this area. The well casing appears to extend to an approximate depth of 80 ft. b.g.s. The shallow surface soils in this area contain lube oil range TPH and VOCs at levels that exceed MTCA Method A Clean Up Levels. Water samples S-20-W and S-24-W reported the presence of Metals at levels that exceed MTCA Method A Clean Up Levels. Water sample S-W-W was obtained from the waters present in the "out of service" well casing. Laboratory analyses results for water sample S-W-W report no presence of gasoline range TPH, diesel fuel range TPH, lube oil range TPH, Metals, and/or VOCs ar levels that exceed MTCA Method A Clean Up Levels. The “out of service” well casing was properly abandoned/closed by Licensed Well Drillers from Holt Services Inc. Area #4 - Storm Water Pond Portion of the Site A storm water collection pond is located on the central southern portion of the site. The storm waters were pump from this collection pond for permitted discharge. In earlier years the waters were pumped/transferred to a treatment cell consisted of layers of oyster shells located near the southeast corner of the subject property and then were released into the wetland/stream area that borders the eastern portion of the property. In recent years the waters collected in the pond were pumped/transferred into a catch basin that is located near the southwestern portion of the property. The catch basin discharged to the City of Renton sewer. 4 Laboratory analyses results for soil samples obtained from the shallow soils in the areas surrounding this pond reported no presence of gasoline range TPH, diesel fuel range TPH, and/or lube oil range TPH. Laboratory analyses results for groundwater sample S-26-W, obtained from the shallow groundwater in the areas near the pond reported the presence of lube oil range TPH, Metals and Vinyl Chloride at levels that exceed MTCA Method A Clean Up Levels. Area #5 - Eastern Boundary of Site Laboratory analyses results for investigative groundwater sample S-17-W, obtained from a location along the central portion of the eastern perimeter of the site, reported the presence of Lead at levels that exceed MTCA Method A Clean Up Levels. Laboratory analyses for investigative soils sample S-18-3, S-18.5-2, and S-18.5-4 confirmed the presence of gasoline range TPH, lube oil, Benzene, and/or Metals at levels that exceed MTCA Method A Clean Up Levels in the shallow soils present along the southern portion of the eastern perimeter of the site. Laboratory analyses results for investigative groundwater sample S-18-W, obtained from a location along the southern portion of the eastern perimeter of the site, reported the presence of Arsenic at levels that exceed MTCA Method A Clean Up Levels. On March 15, 2018, a total of six (6) test pits were recently excavated along the Eastern Boundary of the subject property and directly adjacent to the neighboring wetland area. Solid waste/metal debris was encountered at various depths during the excavation of the test pits which restricted deeper excavation in selected pits. Laboratory analyses results for test pit soil samples R1-2, R1-2.5, R1-4, R3-5, confirmed the presence of gasoline range TPH and/or BTEXs at levels exceeding applicable MTCA Clean Up Levels at various depths in test pits R1 and R3. Groundwater flowed into the lower portions of these test pits. Groundwater Monitoring Well Installations and Groundwater Monitoring Events On August 9 and August 10, 2017, and March 9, 2018, eight (6) groundwater monitoring wells were installed at selected locations on the subject property. The wells were installed by licensed well drillers using a truck mounted rotary auger drill ring supplied by Holt Services Inc. The elevation of the Top of Casing in each monitoring well was professionally surveyed by DOWL. Groundwater samples were obtained from each of the six (6) of on-site groundwater monitoring wells on August 25, 2017. Groundwaters were present at depths ranging from 3.416 to 7.226 feet b.g.s. Groundwater elevation measurements and groundwater sampling services were provided by Blaine Tech. 5 Mr. John Kane, Washington State Licensed Hydrogeologist #1193, determined the direction of groundwater flow was to the west on this date. Groundwater samples were obtained from each of the six (6) of on-site groundwater monitoring wells on January 25, 2018. Groundwaters were present at depths ranging from 1.106 to 5.346 feet b.g.s. Groundwater elevation measurements and groundwater sampling services were provided by Blaine Tech. Mr. John Kane, Washington State Licensed Hydrogeologist #1193, determined the direction of groundwater flow was to the northwest on this date. Laboratory analyses results for groundwater samples MW1, MW2, MW3, MW4, MW5, and MW6 reported no presence of the site’s contaminants of concern at levels exceed MTCA Method A Clean Up Levels. On March 9, 2018, groundwater monitoring wells MW7 and MW8 were installed at selected locations on the western portion of the subject property near East Valley Road. Laboratory analyses results for water samples obtained from these two (2) newly installed wells reported no presence of the site’s contaminants of concern at levels exceed MTCA Method A Clean Up Levels. Groundwater elevation measurements obtained during the groundwater sampling events indicate that the direction of groundwater flow is to the west in the dryer seasons (lower groundwater elevations) and to the northwest in the wetter seasons (higher groundwater elevations). 4.0 Summary: The results of these environmental investigations report no presence of Hexavalent Chromium (Chrome VI) in the shallow subsurface soils on the subject property. The results of the recent on-site investigations of the shallow subsurface soils have identified the above listed areas of concern where the confirmed presence of gasoline range TPH, lube oil range TPH, and/or VOCs, at levels that exceed applicable clean up levels extends to depths up to 10 ft. b.g.s. on selected portions of the subject property. The results of the recent on-site investigations of the shallow subsurface soils and groundwater have identified the above listed areas of concern where the confirmed presence of gasoline range TPH, lube oil range TPH, and/or VOCs, at levels that exceed applicable clean up levels is restricted to surface and subsurface soils present at depth of 2 feet b.g.s. or lees on a large portion of the subject property. The results of the recent on-site probe investigations of the groundwater, present at selected locations on the subject property, have identified the above listed areas of concern where the presence of gasoline range TPH, lube oil range TPH, and/or VOCs, at levels exceeding MTCA Method A Clean Up, are present in the groundwaters sampled using a probe. 6 Groundwater samples obtained from each of the eight (8) on-site groundwater monitoring, wells reported no presence of the site’s contaminants of concern at levels that exceed MTCA Method A Clean Up Levels. The results of these investigations indicate that on many sampled portions of the subject property, the contaminated soils in these areas are limited to depths of 4 feet b.g.s. or less. Also, in some of these areas, the adversely impacted soils are limited to depths of 1 feet b.g.s. or less. Sincerely, Paul W. Stemen Vice President East Valley RdMW-6 MW-2 MW-3 MW-1 MW-4 MW-5 14.16' 13.87' 15.05' 14.27' 14.47' 14.53' 14.0'14.25'14.5'14.75'15.0' Figure 1 Groundwater Elevation Contours Phase II Environmental Site Assessment 3400 East Valley Road Renton, WA N Approximate Location of Property Boundary Project No. 51213 Approximate Building Outline Approximate Location of Fencing Approximate Location of Groundwater Monitoring Well and Groundwater ElevationMW-2 15.05' Estimated Groundwater Elevation Contour Wells Surveyed on 8/30/17 A B