An unknown volume of diesel fuel estimated to be greater than 25 gallons was released on to the surface of the Florida’s Turnpike near Milepost (MP) 50 Northbound. An unknown volume of the fuel entered into a nearby storm water catch basin that discharged to an outfall structure into the swale on the shoulder of the southbound lane. We were contracted by Florida’s Turnpike Enterprise to evaluate and abate environmental concerns resulting from the release.
During the initial response, sorbent materials and a vacuum tuck were utilized to contain and recover diesel fuel from the roadway, storm water catch basin and outfall structure. Potentially impacted soil at the mouth of the outfall structure was covered with visqueen to prevent the leaching of contaminants to groundwater during possible future precipitation events.
We assessed the areal extent of vadose zone contamination in the swale area. Soil samples were collected from 14 soil borings and were screened in the field using a properly calibrated Thermo Scientific Toxic Vapor Analyzer (TVA- 1000) equipped with a flame ionization detector (FID). Based on the results of the limited soil assessment, the areal extent of impacted soil was approximately 25 feet by 12 feet and extended to a depth of 3 feet bls.
Based on the location of the storm water catch basin and outfall structure, we prepared maintenance of traffic plans (MOTs) for the simultaneous closure of the left travel lane of the northbound Florida’s Turnpike and the shoulder of the southbound lane of Florida’s Turnpike. The MOTs were approved by Florida’s Turnpike Enterprise with the condition that the lane closure be performed at night. We performed the cleanout of the impacted storm water catch basin, outfall structure and associated piping at night.
Approximately 23 tons of contaminated soil was excavated from the swale area. Post excavation OVA soil screening was performed to confirm that all accessible contaminated soil was removed. A confirmation soil sample was collected from the base of the excavation for laboratory analysis. Upon completion of the source removal activities, the excavation was backfilled to grade with crushed limerock and the area was re-surfaced with Bahia grass.
Following the cleanout of all impacted structures and the removal of all accessible contaminated soil, we submitted a Source Removal Report recommending no further action at this site.