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Larkspur Estates Soil&Groundwater Sampling on the same day as we have scheduled the Pombo investigation on Lammers Road, June 6, 1999. We are submitting this abbreviated Work Plan in anticipation that we may obtain approval for soil and groundwater sampling prior to June 6, 1999. The scope of work will not include geological interpretation of the subsurface soils. Larkspur is not a known contamination site and we are only concerned with the potential of petroleum migration from offsite, south of the development. 2.0 WORK PLAN M.J. Kloberdanz & Associates proposes to drill up to 3 Geoprobe borings to a maximum depth of 25 feet in the Larkspur Estates development. One soil sample will be obtained from each boring location for laboratory analysis. Water samples will be obtained from all Geoprobe borings. The borings will be drilled on lots 99, 104, and 108 and depicted in the Tentative Subdivision Map (Attachments). Soil samples will not be collected for geological interpretation. Soil and water samples will be delivered under chain of custody to an analytical laboratory licensed by the State of California for hazardous materials work. The samples shall be analyzed for Total Extractable Petroleum Hydrocarbons, BTX&E (Benzene, Toluene, Xylene, and Ethyl Benzene), and Oil & Grease. A Technical Report, which documents and discusses all of the activities and laboratory data involved with the project to date will be generated at the conclusion of the project. The report will include an executive summary of the investigation activities and results, a tabulation of all soil and groundwater data, laboratory data sheets, and any recommendations for further work if data warrants it. The report will be endorsed by the licensed professional responsible for the work. 2.1 Drilling Permits will be obtained, if necessary, for the borings before drilling begins. The soil boring will be accomplished using a mobile mounted Geoprobe" Systems drilling rig, Model 5400, employing the use of a 1.25"hollow probe rods. The contractor conducting the drilling will posses a valid C-57 license and proof of workman's compensation insurance. All drilling equipment will be thoroughly steam cleaned before drilling begins to prevent the introduction of contamination from off site, and between borings to prevent cross contamination. The borings will not be logged. All borings will be drilled in such a manner as to prevent cross contamination between strata. Water samples will be taken at the soil/groundwater interface (if encountered), and the borings will then be terminated with a cement and three percent (3%)Bentonite mixture. 2