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FROM : GRD PHONE N0: 9 267 5370 Mar. . 09 1999 11=48IM PS be obtained prior to beginning field work Three soil bb monitoring wells are proposed at the locations shown on Figure 2. All drilling equipment shall be thoroughly cleaned prior to drilling and between individual borings to prevent the introduction o F contaminants from off site or between boring locations. The soil borings shall be advanced with hollow-stem drilling equipment fitted with a bit with sufficient diameter to drill a boring in which a two-inch diameter mon toring well can be installed. Borings shall be logged by a California Registered Geologist using the I Ynified Soil Classification System. A log I � of each boring, including; soil and lithologic descriptions, c lepths of water bearing zones, petroleum contamination shall be kept during the drilling operation. Soil samples shall be collected usingindustry-standard stry-standard' and sample handling procedures: Soil . samples shall be collected at depth of four and eht feet bg using a split barrel sampler driven ahead , of the bit. The saxrpler tool shall be fitted with two-inch er, clean,brass sleeves to retain the sample for transport to the laboratory. The brass sleeves be sealed with Teflon sheet and plastic end caps. The well borings shall be advanced to 20 feet bgs or appy xirnately 10 feet below the groundwater, level. The static groundwater level was n*awred at approximately nine feet bgs on 21. January 1999: � The monitoring wells shall be constructed with two-inch solid PWC casing and 0.020-inch slatted casing(factory-milled well screen). The well screen shall set from approximately five to 20 feet bgs. The solid casing shall extend from to approximately .5 feet below ground surface to allow a flush surface completion. A filter pack of#3 sands be placed around the well screen to approximately one foot above the screen. A one foot filter of bentonite Chips shall be placed on top of the filter pack_ The sanitary seal shall extend from t ie top of the filter seal to approximately ane foot bgs. The surface shall be completed with a traffic-rated vault box. The monitoring wells shall be surveyed to obtain the relative elevations of'the ground surface and top- of-casing(TUC), and the horizontal positions. The depth to groundwater shall be measured from the TUC to determine the groundwater gradient. The monitoring,wells shall be developed until the water appears clear of sediment or until five well casing volumes have been extracted. Water extracted from the monitoring wells shall be placed into appropriate containers and left on site for disposal by the property owner. The groundwater in the well shall be allowed to stabilize for at least 24 hours after w4l development before commencing with samPfing- 13. Collection wd—A_na_Iygg of GroundwaAer Samnles Prior to sampling, the static groundwater level shall be measured from the TOC for groundwater gradient determination_ As monitoring well purging Pro s, the extracted groundwater shall be evaluatedfor the field parameters pK electrical conduct' , and temperature. At least five well volumes shall be extracted in.preparation for sampling. WORKPLAN FOR LIMITED SOIL AND GRO UND WATER INTIESTIGATION SUNNYSIDF, PRODUCE, THO.RNTON, CALIFOIWU PAGE 3 i 1