ARCHIVED REPORTS_XR0012177 - Laserfiche WebLink

Home Browse Search

LM LEEDSHILL HERKENNOFF, INC The Arco AM/PM 111Fac 1 z ty i s l ocated south of the prof ect s i to on the ad j scent 1 of. In this study, four soil borings were drilled, one of which was completed as a monitoring well . Laboratory analysis of soil samples collected from the four soil borings and a groundwater sample collected from the monitoring well indicated no presence of petroleum hydrocarbon constituents. It was therefore concluded by BCA that the AM/PM site was free of petroleum hydrocarbon contamination. In April of 1988, BCA prepared a report entitled, "Hydrocarbon Evaluation Study for Roek Brothers Property, Market Street and Wilson Way, Stockton, California " In this investigation BCA drilled 3 test borings. Two of the borings were sampled at depths ranging from 2 to 20 feet. Although an on-site organic vapor detector indicated the presence of organic material , laboratory analysis indicated no presence of total petroleum hydrocarbons (TPH) except for a sample obtained from Boring 1 from a depth of two feet; the TPH concentration for this sample was 195 ppm. BCA concluded that there was shallow contamination present in the soils in the vicinity of Boring 1 and recommended that the contaminated soils be excavated and aerated to reduce the concentration level It was later determined that BCA had conducted its April 1988 investigation without contacting or obtaining appropriate permits from the Public Health Services, Department in San Joaquin County. Consequently, the initial site assessment had to be repeated. On April 24, 1989, BCA presented the findings of their second investigation of the Roek Brothers Property in a report entitled, "Report of Test Boring and Monitoring Well Installations, 102 South Milson Way, Stockton, California. " In this investigation, BCA installed three soil borings, which were converted to monitoring wells, plus an additional soil boring. Laboratory analyses were conducted on soil samples and groundwater samples collected from these new soil borings and monitoring wells. Laboratory analysis indicated very trace to non- detectable concentrations of petroleum hydrocarbons in the soil samples collected. Groundwater samples collected from monitoring wells (MW) 1 and 3 showed trace or non-detectable levels of benzene, toluene, xylene & ethylbenzene (BTX&E) and total petroleum hydrocarbons (TPH) ; however, groundwater samples taken from MW 2 indicated the presence of both BTX&E and TPH. It was BCA's conclusion that it was unlikely that the main fuel tanks previously removed from the site were responsible for the groundwater contamination found in MW 2 since no indications of contaminants existed in the upper 40 feet of soils. However, boring logs indicated hydrocarbon odor at various shallow depths in each of the monitoring well borings. It also should be noted that in BCA's previous investigation conducted in April of 1988, soil contamination was detected at a depth of two feet in Boring I adjacent to the location of MW 2 The inconsistencies in these previous reports prompted Neumiller and Beardslee to contract with LH to conduct an additional site investigation to verify the presence or absence of soil and/or groundwater contamination. The locations of BCA's previous soil borings and monitoring wells are shown on Figure 2, It should also be noted that BCA's numbering of the monitoring wells was inconsistent throughout their investigation. LH has attempted to interpret n �o i