WORK PLANS - Laserfiche WebLink

Home Browse Search

4� d 1.0 INTRODUCTION At the request and authorization of the property owner, BSK & Associates (BSK) has L. prepared this Workplan for investigation of petroleum hydrocarbons in soil and groundwater from a former on-site underground fuel storage tank (UST). The contamination was revealed by sampling and chemical analyses during the removal of an UST from the property, and during an ensuing investigation of the site. Figure 1 presents a Vicinity Map of the site. Site information is as follows: L. Site Location: 26500 Nowell Road Thornton, California 95686 Im Tank Owner: Ms. Pamela Lopez Contact: Mr. Robert Holiday P.O. Box 393 Thornton, California 95686 (209) 794-0205 1.1 Project History 'r One 500-gallon gasoline tank was exhumed and removed from the site on October 9, 1989. Chemical analyses were performed on a soil sample obtained from beneath the UST. Results of the analyses for Total Petroleum Hydrocarbons as Gasoline (TPH-G) and gasoline constituents Benzene, Toluene, Ethylbenzene & Xylenes (BTEX) indicated that a release of petroleum hydrocarbons had occurred. In November 1994, three soil borings were drilled and sampled on the Lopez property by RAH Environmental, Inc. (see Figure 2, Site Plan). Two of the borings were drilled in conjunction with a UST investigation of the adjacent Tri-Valley Growers property, and one boring was drilled and sampled to evaluate the vertical extent of impacted soil in the vicinity of the former Lopez UST. The boring drilled to evaluate the vertical extent of the release from the Lopez UST was advanced through the former UST location. Chemical analyses of soil samples obtained from the boring indicated that petroleum hydrocarbons were present to below the groundwater surface. Groundwater, sampled through the hollow-stem auger, was also analyzed and results of analyses suggest that groundater in the vicinity of the UST had been impacted by a release of petroleum hydrocarbons. Results of analyses on soil and groundwater samples from the other two borings resulted in the following conclusion from ,,. RAH Environmental: "The presence of soil and water hydrocarbon contamination in SBA, and the lack of �.., soil contamination and the much lower level of water contamination in SB4, indicate that the contamination found in SBA most probably results from the former gasoline storage tank.,, WarW&m-07400008-RrAKd hnc 1995 1 Li &Associates i.r