ARCHIVED REPORTS XR0011187 - Laserfiche WebLink

Home Browse Search

y Mr Kenneth R Earnest June 4, 1942 Page 2 Soil Borings Soil samples collected from the borings consisted of silty clay, sandy silt, silt, sand, clayey slit, clayey sand, and sandy clay For example, the lithology of soil samples collected from soil boring MW-3 is described in detail by depth as follows from below the asphalt road base to 13 feet below grade, the soli encountered consisted of a silty clay, from 13 feet to 22 5 feet a sandy silt was encountered, under the sandy silt a clayey silt was present to 28 5 feet, below this level, sand was present to 35 feet, from 35 to 50 feet, a silty clay was encountered, under the silty clay, sand was present to 57 feet, below the sand, a clayey silt was encountered to 63 feet, from 63 to 68 5 feet, a silty sand was present, a clayey silt was present beneath the salty sand to 73 5 feet; below the clayey silt, a sandy silt was present to 79 feet, and from 79 to 83 feet, the total depth of the boring, a silty clay was encountered The strata between borings does not appear to be laterally continuous Contacts between the soil types varied between gradational and sharp Soil boring logs containing detailed descriptions of soil conditions for all boruigs installed are included in Enclosure B Soil Sample Analytical Results A portion of each soil sample collected from the soil borings was sealed in a plastic bag and allowed to reach ambient air temperature The headspace of the bag was then screened in the field with a photoionization detector (PID) The highest PID reading for each sample was recorded on the right-hand side of the boring logs (Enclosure B) Soil samples were selected for chemical analysis on the basis of PID screening results and the location of the soil samples in relation to the most likely source of petroleum constituents Eighteen soli samples were submitted for analysis of concentrations of BTEX, TPHg and TPHd Analytical results of soil samples submitted by AMV are summarized in Table 1 Copies of certified analytical reports are contained in Enclosure D. Ground Water Level Measurements Ground water level measurements were collected from each monitoring well on April 17, 1992 (Table 2) Ground water was present at depths ranging from 7129 to 72 02 feet below the top of the well casing Water level measurements indicate an inferred direction of ground water flow toward the southeast as illustrated on Figure 3 On April 17, 1992, the ground water gradient was approximately 0 001 foot per foot Ground Water Analytical Results On April 17, 1992, ground water samples were collected from the three on-site monitoring wells (MW-1 MW-2, and MW-3) Samples were collected as described in Enclosure A Each ground water sample was analyzed for BTEX, TPHg, and TPHd, by state and federal EPA/DHS-approved methods Analytical results are summarized in Table 3 Copies of certified analytical reports are contained m Enclosure E The inferred distribution of dissolved benzene in groundwater beneath the site is illustrated on Figure 4 ACTON 0 NQCKELSON • van DAM, INC. Consulting Sesenhsts, Engineers, and Geologists