FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

volatile aromatics benzene, toluene and xylene), total lead and ethylene dibromide (EDB). No petroleum hydrocarbons or EDB were detected in the soil samples. However, total lead was detected in the sample collected from beneath the gasoline tank's (sample SE) at 48 mg/kg (parts per million). The method detection limits (MDL's) utilized by Canonie were 0.2 mg/kg for volatile aromatics; 1.0 mg/kg for TVPH; and 5.0 mg/kg for total lead. However, ;because the MDL's utilized are no longer in accordance with county and state requirements, the PHS/EHD requested the collection of additional soil samples from the former tank excavation area. 2.3 Groundwater Depth and Gradient According to the San Joaquin County Flood Control Map (Fall, 1993), depth to groundwater in the area is between 70 and 80 feet. The regional groundwater gradient direction is generally easterly. However, the gradient direction in the area can vary' greatly. 3.0 PROCEDURES 3.1 Drilling and Sampling On August 11, 1994, two borings were drilled using a CME75 HT drill rig. The drill rig and two-man crew were supplied by Mitchell Drilling Environmental Corp.: Borings BM-1 and BM-2 were drilled in the area of the fonder UST and advanced to a depth of 20 feet. Soil cuttings were placed in 55-gallon drums and stored on-site. For both soil borings, discrete soil samples were collected ahead of the d,rill.bit using a:split- tube sampler loaded with three pre-cleaned 2-inch by 6-inch brass sleeves. Samples were collected at depths of 10, 15 and 20 feet in both borings. To avoid cross contamination, the sampling equipment was washed in an alconox solution and rinsed twice with water prior to each sampling run. For each sample, both ends of the lead tube were covered with aluminum sheets, capped and sealed with tape. The samples were then stored on ice and transported under chain-of- custody to Pan-Agricultural Labs, Inc. (PAL) in Madera, California. Selected samples were analyzed for TPH as gasoline and diesel, BTE&X and total lead in accordance with EPA methods 8015m, 8020 and 6010, respectively. 3.2 Logging Soil was extruded from the second brass tube and screened for the presence of organic vapors using a photo-ionization detector (PID: Thermo Environmental 580A, 10.0 eV, calibrated to isobutylene); PID readings were recorded on the boring logs. Each boring was Co Iog�ml Audh Sew»aa•Inc. 4A � SG9 06 M-OVBLUE MAGIC RPT