ARCHIVED REPORTS XR0012575 - Laserfiche WebLink

Home Browse Search

s, r: 1.0 INTRODUCTION The site is a concrete and asphalt paved truck fueling facility dispensing regular and unleaded gasoline and diesel fuel from six fuel islands (Figure 1 - Site Plan w/ Ground- Water Elevation Data). The underground tank cluster lies east of the fuel islands and consists of five tanks: two 10,000-gallon diesel tanks manifolded together,one 8,000-gallon diesel tank, one 8,000-gallon regular gasoline tank, and one 7,500-gallon regular gasoIine tank. There is also a'2,000-gallon unleaded gasoline tank approximately 30 feet south of the lunger fuel island in the center of the site. 4 S A site assessment was requested by the San Joaquin County Department of Public Health o , Services/Environmental Health Division (PHS) because of tank testing failures and ' y unauthorized fuel releases at the site. In May 1990,Environmental Science&Engineering, saP Inc.(FSE)drilled and sampled soil borings around the product lines and underground fuel tanks to assess the vertical and Iateral extent of hydrocarbons in the soil. The results of this r.r investigation are presented ir- ESE's "Report of Site Assessment", dated June 14, 1990. Figure 2-Approximate Extent of Soil Containing Hydrocarbons shows that hydrocarbons extend to at least 50 fest deep,but are apparently restricted to the area around the product R litres and underground tanks. Because of the depth of hydrocarbons in the subsurface soil, a ground-water investigation was recommended. 2.0 GROUND WATER INVESTIGATION One ground-water monitoring well,UST-1 was drilled and sampled on September 20, 1990 downgradient and within ten feet of the area of deepest penetration of hydrocarbons in the soil (Figure 2), following a revised workplan approved by San Joaquin County Department of Public Health Services, Environmental Health Division. �. 2.1 Drilling and Soil Sampling Procedures Well UST-1 was drilled with 10-inch diameter hollow-stem augers for construction of a 4- inch diameter monitoring well. Soil samples were obtained at 10-foot intervals in three 6- t.