COMPLIANCE INFO - Laserfiche WebLink

Home Browse Search

Evaluation of Hydrocarbons May 17, 1990 Waterfront Redevelopment, Stockton, California AGS 39048-2W PROPOSED WORK The proposed investigation is designed to explore the lateral extent of hydrocarbons in soil and groundwater beneath the City of Stockton's Waterfront Redevelopment Property and to assess areas that hydrocarbon vapors were previously detected and areas that have not been investigated. The following tasks are proposed and discussed in the following sections: o Drill five soil borings to a maximum depth of approximately 20 feet and four soil borings to a maximum depth of approximately 30 feet (approximately 10 feet below the expected ground-water surface). The soil borings will be terminated if a low-permeability zone (aquitard) at least 5-feet thick is encountered below the ground-water surface. The locations are shown on the Generalized Site Plan. o Collect and classify relatively undisturbed soil samples at 5-foot intervals or obvious changes in soil type, from approximately 5 feet below grade to the total depth of each boring. The soil encountered in the borings will be logged in accordance with the Unified Soil Classification System. o Analyze soil samples from each soil boring for total petroleum hydrocarbons (TPH) as gasoline and diesel fuel using modified Environmental Protection Agency (EPA) Method 8015 and benzene, toluene, ethylbenzene, and total xylene isomers (BTEX) using EPA Method 8020. o Backfill the 20-foot deep soil borings to the ground surface with a cement- bentonite slurry. o Construct 2-inch-inner-diameter groundwater monitoring wells in the 30-foot deep soil borings. o Develop, purge and sample the newly constructed monitoring wells. o Analyze the ground-water samples for TPH as gasoline and diesel fuel using modified EPA Method 8015 and BTEX using EPA Method 602. 7 N AVj01ie0' G90Systeins