The site is located east of the intersection of state Route 16 and state Route 668, just south of the state Route 16 eastbound lanes, approximately 400 feet west of Mile Marker 28, in Licking County. The spill occurred due to a gasoline tanker truck accident. The truck came to a rest in a swale located on the boundary of the Ohio Department of Transportation (ODOT) right-of-way and the CSX railroad property. The immediate vicinity of the spill area is located between a four-lane, limited-access highway and an active railroad. Locally, the area is rural/agricultural.
On March 5, 2001, an Englefield Oil tanker truck carrying gasoline traveling eastbound on state Route 16 overturned on the south median of the four-lane highway. The tanker was carrying approximately 8,000 gallons of gasoline. Three of four compartments on the tanker failed, causing a release of approximately 5,100 gallons onto the ground surface. The gasoline immediately soaked into the surrounding soils. A portion of the gasoline flowed east approximately 800 feet through a drainage swale where it encountered an unnamed stream, which flows south to the Licking River. Local fire departments, including the Newark Hazmat Unit, and the Ohio EPA Division of Emergency and Remedial Response (DERR), Emergency Response Section responded to the incident. The Englefield Oil Co. was directed to initiate cleanup of the spill, which resulted in their retaining B&B Underground to clean up the spilled gasoline and contaminated soil. SRW Environmental (SRW) was also retained by Englefield Oil to evaluate the extent of subsurface contamination.
As a result of free product recovery at the immediate spill area and along the drainage swale, more than 1,200 gallons of gasoline were recovered during the emergency response. Therefore, an estimated 3,900 gallons of gasoline remain unaccounted for following the emergency response.
As part of the immediate response, soils were excavated at the spill site and along the drainage swale to the east. Due to the presence of sandstone bedrock, the placement of a trench drain collection system was not possible. Soil and sandstone were removed in the immediate spill area until a confining clay/mudstone layer was encountered. To further define extent of contamination, test pits were advanced in the farm field, south of the railroad tracks and spill area. No gasoline was encountered.
During June 2002, SRW installed nine soil borings south of the spill area and both north and south of the railroad tracks (SB-1 through -10). Soil borings were drilled to a depth of 12 to 16 feet below the surface where a impermeable mudstone layer was encountered. No ground water was encountered in any of the borings. Soil samples were analyzed for benzene, toluene, ethylbenzene, xylene (BTEX) and Total Petroleum Hydrocarbons (TPH). BTEX was identified in eight of nine borings and TPH in three of nine borings. Benzene concentrations ranged from below detection limits (ND) to 1.8 mg/kg. Toluene ranged from ND to 23 mg/kg. Ethylbenzene ranged from ND to 4.3 mg/kg. Xylene ranged from ND to 75 mg/kg. TPH ranged from ND to 820 mg/kg.
SRW also installed three monitoring wells. These wells were located south of the railroad tracks and north of the neighboring farm field. They were sampled on six occasions between June 2002 and March 2005 for BTEX and MTBE.
In MW-1, concentrations of all BTEX compounds were detected (benzene at 0.79 - 25 mg/L; toluene at 1.4 - 43 mg/L; ethylbenezene at 0.034 - 4.0 mg/L and xylene at 0.41 - 26 mg/L). MTBE was detected on one date at 0.032 mg/L. The six concentrations for BTEX compounds were analyzed by Ohio EPA using the Mann-Kendall Statistic for trends. Decreasing trends were identified for benzene, toluene and xylene at the 90 percent confidence level. A decreasing trend was identified for ethylbenzene at the 80 percent confidence level.
In MW-2, concentrations of all BTEX compounds were detected (benzene at 0.11 - 6.6 mg/L; toluene 0.012 - 27 mg/L; ethylbenezene at 0.005 - 2.4 mg/L; and xylene at 0.097 - 12 mg/L). MTBE was not detected. The six concentrations for BTEX compounds were analyzed by Ohio EPA using the Mann-Kendall Statistic for trends. Decreasing trends were identified for benzene, toluene and ethylbenzene at the 90 percent confidence level. A decreasing trend was identified for xylene at the 80 percent confidence level.
In MW-3, concentrations of all BTEX compounds were detected during June 2002 (benzene at 22 - ND mg/L; toluene 37 - ND mg/L); ethylbenezene 1.6 - ND mg/L; and xylene at 11 - NSmg/L). MTBE was not detected. The BTEX compounds were not detected for the following five sampling events. SRW has indicated that they believe that the June 2002 sample was mislabeled. The five rounds of data with no BTEX detections suggest that this location is not impacted.
During September 2002, a punch bar sampling investigation was performed by SRW at the former soil excavation area and east along the drainage swale. A
flame ionization detector (FID) was used to determined if residential contamination remains. Punchbar sampling indicated residual soil vapor in the area of the excavation at the spill site (0 - 1428 parts per million (ppm)). Samples from the western end of the drainage swale had concentrations ranging from 0 to 8.6 ppm. Samples from the eastern end of the drainage swale had concentrations ranging form 0 to 181.4 with one very high detection of 20,000 ppm. Migration of vapors beyond the edges of the swale could not be evaluated due to the presence of sandstone bedrock within the top 1 to 2 feet of the surface.
During the April 2003 ground water sampling event, Ohio EPA performed an additional probe sampling investigation of the drainage swale to follow up on the September 2002 work. A probe was used to create small holes in surficial soil at approximately 20 locations along the base of the swale and at several locations with sediment deposition in the unnamed tributary near its confluence with the swale. A photo ionization detector (PID) was used to monitor possible volatile compounds a each hole. Readings ranged from 0 to 11.0 ppm. Most readings were at the lower end of that range. No odors or visual indications (e.g. a sheen) were noted while performing this work. Special care was taken to collect samples in the area where the previous 20,000 FID detection had occurred during September 2002. However, no elevated readings were detected.
During March 2005, SRW installed 11 additional borings (SB-10 through -20). Soil boring were drilled to a depth of approximately 12 to 20 feet below the surface where ground water or auger refusal at bedrock occurred. The approximate depth to ground water ranged from 9 to 15.5 feet. Soil samples for laboratory analysis were selected based upon field FID screening. Soil samples were analyzed for BTEX and MTBE. No BTEX compounds or MTBE was detected. These analytical results suggest no downgradient impacts in soil from the gasoline spill.
Ground water samples were collected from five of the soil borings (SB-13, -14, -16, -17, and -19). Ground water samples were analyzed for BTEX and MTBE. These borings were completed at locations topographically below and presumed to be hydrogeologically downgradient of the thee monitoring wells. The analytical results for these ground water samples indicated that BTEX and MTBE were not detected with one exception (benzene was detected at 0.004 mg/L in SB-13). This work was overseen by Ohio EPA/Division of Drinking and Ground Waters (DDAGW). Results suggested that installation of a new downgradient well was not warranted. These analytical results suggest no downgradient impacts in ground water from this gasoline spill.
Downgradient land uses are limited by the easement that the U.S. Army Corps of Engineers maintains on the flood land for the Dillion Reservoir. Therefore, residential development is not anticipated to occur. SRW submitted a risk assessment, following Bureau of Underground Storage Tank Regulations (BUSTR) criteria, as part of their April 19, 2005, submittal. They concluded that the potential exposure pathways were not a concern at the site.
Based on aerial photographs, approximately seven residences are located near the spill area. These seven residences are upgradient of the spill area and the closest is over 650 feet away. No residences are located downgradient of the area impacted by the spill (between Route 16 and the Licking River).
Based upon the results of work performed at the site documenting that minimal risk remains at the site, no additional work is necessary at the spill site. A letter stating that no additional work was necessary was sent to the Englefield Oil Co. on June 21, 2006.
Summary date: June 2006