Starfire Express Tier 1 Source Investigation and Tier 2 Evaluation – ODOT – Hudson, Ohio
STONE completed additional subsurface investigations, including additional soil borings and monitoring well installation, as part of the modified Tier 1 Source Investigation Deficiency Investigation and Tier 2 Evaluation for a former Starfire Express gas station site. The former gas station and associated underground storage tank (UST) system were previously removed as part of road reconfiguration and improvements. Previous investigations were completed at the site, but additional soil and groundwater investigations were necessary. STONE completed sixteen soil borings using a GeoProbe equipped with hollow-stem auger capabilities to the desired depth in a minimum of the uppermost saturated zone. Desired depths were based on the depths of the historical wells previously installed at the site. The soil cores were continuously sampled and screened using a photoionization detector (PID) and soil samples from each boring were analyzed for benzene, toluene, ethylbenzene, xylene (BTEX) EPA Method 8260; methyl tertiary butyl ether (MTBE) EPA Method 8260; total petroleum hydrocarbons (TPH) gas and diesel ranges EPA Method 8015. The submitted samples were also based on the historical wells, with only previously analyzed intervals being submitted. Two soil samples were also analyzed for Fraction Organic Carbon (FOC) for potential future use in site-specific calculations. Two Shelby Tubes of unsaturated soils were also collected for potential geotechnical analysis (classification – gradation, bulk density, porosity). Eight of the sixteen soil borings were converted into monitoring wells. The new wells were developed and purged, and one groundwater sample was collected from each new and existing monitoring well (total 14 groundwater samples) and submitted to an accredited laboratory for analysis. The groundwater samples were analyzed for BTEX and MTBE. Upon receipt of laboratory results, STONE prepared a Tier 1 Deficiency Report for BUSTR of the updated soil and groundwater concentrations. The Deficiency Report proposed that a Remedial Action Plan (RAP) using a monitoring-only approach would be implemented moving forward. STONE continued to collect groundwater data, and the site obtained a “No Further Action” (NFA) letter from the Ohio Bureau of UST Regulations (BUSTR).